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Diffuse bake alpha
It's simpe. I have a plane. On that plane is a texture of a leaf with alpha transparency. Works when I render/switch to rendered preview. Now I want to bake that image of a leaf to another plane, so I have 512x512 texture (instead of some random resolution)

Above is the node set up for the transparent leaf
[![enter image description here][2]][2]
And the material for the "low poly" plane that I need the image baked to, is just an image texture with an empty image connected to diffuse connected to surface output. When I bake it, the places that are transparent in the first material, just become black instead.
https://www.dropbox.com/s/bhmh1l6ikcuiyim/Dandelions.rar?dl=0
Here is the file in case anyone wants to see it-it's ment for UE4 btw. The top layers are the "low poly", more to the right, the lower the texture resolution is, and below them, there are the coresponding "high poly models"
Joke question-How tall are dandelions usually? 15-25cm?

Also, if you just my file, you need to move the low poly planes on teh last 2 morels a bit, the normals are the wrong way

now it's even worse, I get completley nothing when i bake it

In cycle i don't know why you have to create an image texture slot in the node editor of your material and link it to your image. Also try a tranparent shader instead of translucent to bake alpha

Oh, yea, I just noticed I was using translucent instead of transparent. but still. what is suppose to be alpha is just black. I managed to filter it out in gimp tho.

I think i found solution, or rather  Zacharias Reinhardt from yt.
Simple way to render instead of baking foliage bilboards. No black alpha outline will be seen.
https://youtu.be/BtUS8QTsVZA
Other method would be to model HP plant without alpha for baking bilboards. You can add it for other LODs.

Answers that rely only on a link are discouraged and likely to be removed in review.  Please elaborate.

a color inverter helps when i get that black in my transparent images. maybe give it a shot

Please elaborate (preferably with screenshots) where the invert node goes. And if you know it, a short explanation of WHY it works is also good.


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Boolean not working
For some reason the boolean difference won't work. I'm trying to use the "123" to carve holes into the "Cube.622"
https://www.dropbox.com/s/l3n3p2swgzq2z7g/Church.blend?dl=0
link to the file

it looks like it works, the problem is that the faces of 123 barely touch the faces of Cube622, besides that Cube622 is not a closed shape, it has a lot of holes, so it's not considered like "full"

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


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How can I add loops cuts to all the parent selection within an object?
I have a model, that I have selected specific face loops and I used (Shift G) - > Perimeter, which selected all of the same kinds of face loops around the whole model. I then want to add two loop cuts on one of those face loops, and is it somehow possible for those two loop cuts to be inherited over all of the selected face loops ? This way I can only press Ctrl - R only once, and all of those selections will get the same kind of loops cuts. If there is no way, then I will have to do it manually, and this will be very frustrating, because there is over 30 of those faces, and there is a big chance of missing some. If someone knows a technique to do this in a much faster way, please specify it below.

Related: http://blender.stackexchange.com/q/3259/599

Shift+H to hide the everything else while your face loops selected.
Switch to edge selection mode and select one of the short edges
Shift+G to select similar and choose Length from the menu to select all the edge rings.
Hit W and select Subdivide from the menu and in the operator panel or by hitting F6 change number of subdivisions to 2 to make 2 edge loops across all the edge rings.

Thank You! Very good technique. It worked perfectly. I just learned a new thing.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


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Duplicating Vertex Groups
I have made a plane, and I have added one Vertex Group to it, and weight painted it as I desired. I then want another vertex group, but I want to duplicate the initial one, because I want the second vertex group to share the same weight paint as the first one, and I also want to add additional weight paint to the second vertex group.
Is there a way to duplicate vertex groups on the same object ?

You can duplicate a vertex group from the drop down menu underneath the delete (-) button.

That iS THE WORSE UI. Its a down arrow that just loosk like a redundant scroll arrow.  Should be a "..." to show there are more options.

Omg the ui is so bad, I thought the same thing and your comment "solved" it for me.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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Time delay when selecting objects in a python script!
I am trying to create a simple script in python that will allow me to select objects from my scene. What I did, is created a scene, and added 3 objects, a cube, a sphere and a cylinder, and they are named; Cube, Sphere and a Cylinder , respectively. I am trying to create a python script in which I want to select these objects within a time delay. So for example I want to select the Cylinder, then 1 second later I want to select the Cube and then 1 second after that I want to select the Sphere. At the end of my script all 3 objects should be selected.
   In my script they are all getting selected but they all get selected instantaneously at the end of the program. I used the time module for python to create the time delay of 1 second after I select one object, but it doesn't seem like the time delay does anything, because all 3 objects gets selected simultaneously. Here is my python script and blender project.
Firstly, I create an empty list, which i then fill up with the name of all the objects in my scene, in my case its only 3 objects. I then loop through those objects from my list / scene and select them 1 by 1 with a 1 second delay in between. However when the script ends all the objects are selected instantly. And yes, I did unselect everything before running the script.
Does anyone know how I can fix or re write my code, so when I run the script, it will select an object then wait for 1 second and select the other object and then wait 1 more second after that and select the last object.
Of course, I only used only 3 objects in my scene for simplicity reasons, but this script should of course work for any scene and any number of objects.

Modal timer operator
Would suggest not using time.sleep and use a modal timer operator instead.' Example using modal timer operator template.
import bpy

class ModalTimerOperator(bpy.types.Operator):
    """Operator which runs its self from a timer"""
    bl_idname = "wm.modal_timer_operator"
    bl_label = "Modal Timer Operator"

    _timer = None
    ob_index = 0

    def modal(self, context, event):
        scene = context.scene
        if self.ob_index >= len(scene.objects):
            self.cancel(context)
            return {'CANCELLED'}

        if event.type == 'TIMER':
            scene.objects[self.ob_index].select = True
            self.ob_index += 1

        return {'PASS_THROUGH'}

    def execute(self, context):
        wm = context.window_manager
        self._timer = wm.event_timer_add(1, context.window)
        wm.modal_handler_add(self)
        return {'RUNNING_MODAL'}

    def cancel(self, context):
        wm = context.window_manager
        wm.event_timer_remove(self._timer)

def register():
    bpy.utils.register_class(ModalTimerOperator)

def unregister():
    bpy.utils.unregister_class(ModalTimerOperator)

if __name__ == "__main__":
    register()

    # test call
    bpy.ops.wm.modal_timer_operator()

Yes, this is what I am looking for exactly ! I only have one question, how will I be able to use this Modal time operator ? Do I just use this same code at the beginning of my script and then run my script as it is, or do I need to apply some parameters ?

Yes, I got it working, just by running your script ! I am pretty new to python, but could you shed some light on how and why does this modal time operator works ?

Will get  back to it.. need new batteries for keyboard.. took 5 mins to write this comment lol.

Yeah, don't worry!

It ought to function as intended.  Try printing time between iterations.

Did it work for you ?

Yeah, it did OK over here.  I can't say why it would jump past a delay for you.  You've got the most recent version of Blender?

I am using 2.78b.

Possibly due to Python output buffering, using multiple threads to go through the loop.  https://stackoverflow.com/questions/21886233/time-sleepx-not-working-as-it-should  Maybe import sys then call sys.stdout.flush() after sleep  https://stackoverflow.com/questions/44799353/time-sleep-function-not-working

I upgraded and still get the same result. I get the selection occurring instantly at the end of the script. For you, is it selecting one object, then waiting 1 second and selecting the other one and so on, or does it do it all simultaneously?

I put sys.stdout.flush()  after my time.sleep(1) in my for loop , and still get the same result. :(

It waits for me.  Printing time ticks once a second, as shown in the image above.  Seems like a Python bug, but I can't recreate it here.  Could be due to processor or OS, couldn't say.  You might try asking on stackoverflow, and see if someone over there has a better idea of what's going on.  I'd imagine they'll point you to similar pages, but maybe they can explain it better.


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Making a Voronoi Texture affect where an image texture is placed on a model?
I have made a simple rock object. I have added bump map, SPEC map and the diffuse texture. I want to make the rock's texture have variation in its texture. I want to add a voronoi texture that will affect what areas of the model will have the image diffuse texture, and the other parts of the model, I want to be in different saturation. Therefore I want variation in the image texture. So some areas are lighter and more saturated, and the other areas have the diffuse color of the image texture.
Here is my node setup.

I want to make this, because it will add more variations to the texture of the model.

You can add a Color > Hue Saturation Value node and plug the voronoi texture into the Saturation socket.  Values on the voronoi texture closer to 1 will make those areas of the diffuse texture closer to the original saturation, values closer to 0 will be more saturated.

You can add a Color Ramp node after the Voronoi texture to have better control.

Differentiate diffuse map into 2 shaders and control them with mask
In order to make different parts of model being saturated in a different way which is controlled by Voronoi texture, use 2 shaders and plug that texture as a mask.
In the node setup mask is plugged into the Factor input of the Mix Shader:

It makes bottom (saturated) shader affect where the texture is bright and viceversa.
Resulted shaders - top, bottom and masked:

You can do this by adding a voronoi texture and using its "fac" output as the mix controller for the mixing factor of image textures.

Add the Voronoi Texture.

Pluck its factor into the factor of the MixRGB node.

Add Image texture node and plug it into the MixRGB node.
Hopefully this will do the trick


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3D printer simulation
i am trying to build something like a primitive 3D printer in blender using fluid dynamics . I am having real problems to control the fluid dynamics .
i was looking for something like this as a start but better if the fluid is a little less viscous when reaching the print bed ...
https://www.youtube.com/watch?v=Se4v-QRWtYA
the idea is to build a fun low polly structure then actually print the results .
any pointers would be great thanks.

A 3D printer doesn't really push out fluids... Fluid dynamics is the wrong way to approach it I would say.
I would personally try to simulate it more using a particle system replicating small spheroids or cubes, where the particles have 0 motion and randomness out of the nozzle, and become children of the bed plate object to move along with the bed plate in your motion system.
I've designed the chassis of my printer with Blender and am looking at doing something similar for video demo purposes, will post an update if you still need help with that when I get over the hurdles I'm facing.


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making an intersecting curve manifold
i am using blender to make files for digital fabrication , 3D printing and CNC milling . i am working a little project where i have been sketching with beveled curve , my problem is that when the curve intersects the mesh also interects and i need it as a solid object with no interal vertex . does anyone know a good solution to this problem . i have been just trying to stitch it back together myself but it is time consuming and not great results .
many thanks

You can try to keep only a quarter of it so that you can clean it "by inside" and then apply a mirror in order to obtain the whole shape again.

The blend here : http://www.pasteall.org/blend/42115

this does speed things up a little but is there no way to stop the internal vertex to form in the first place . i want to use this technique more than once so it would be nice to find cleaner solution .

once the curve is converted to mesh, one thing can be tried : assign the inside vertices to a group and shrinkwrap this group to a plane... ?

Another solution : https://i.gyazo.com/386a2fd12089df20345e628d12e431a5.png. Spin a circle 180° duplicate and bridge them.

thanks for all the ideas . as i want to use this technique often i needed to find a quick solution to make manifold and loose the internal vertex . the best result i found was to actually export to mesh mixer and make solid then bring back into blender .


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physics engine modeling

i am trying to build something like this but using physics engine but running into lots of problems . i have made the main form in soft body then i am trying to drop a rigid body in as the buttons . it is close to working but ultimately the rigid bodies penetrate and pass through the soft body .
i have also tried to create an elastic material and inflating it but will little success .
i am struggling to find good resources for the physics engine a good overview would be great. does someone know any good overview documentation that could guide me a little to do jobs like this .
should i be using ringing somehow or should it be manageable just with soft and rigid body dynamics ?

I think it would be useful to explain why you have chosen to create this with physics as this seems like a very complex way to make this.

yeah it does make it more tricky i could model this quite easy i think but I want to start understand the physics engine better as a nice way to make models without to much control . it is a way to bring a bit of random do a model . or a way to get a good sense of weight . i ultimately  want to inflate , stitch and apply gravity to objects to slightly remove my hand from the process . the finished models would be printed or machined .

Obvious question, why not make this a mesh or a bunch of interconnected meshes and then make them soft body or run collision against them? Perhaps your object is too complex as one mesh, you need a few. Have you tried just creating a mesh of this? Is the point you wa t intro deform when something lands on it? Do you have a .blend file?


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complex internal vertices
i have managed to build this shape but i cant find a nice way to remove internal vertices. the "bean" was made with polyverts in the form of spheres so this shape is made from complete spheres and all the geometry is still there . i want to try printing it so need to remove all of that . any nice ideas . could not use the shrink wrap well for it .
thanks

BoolTool add-on
I'm not sure on what you mean by saying polyverts, but I'm am assuming that is something similar to parenting+vertex duplication...

So starting from a similar situation, after make the duplicate real, we have a plenty of different objects.
Download and install the BoolTool add-on that will allow us to merge all the objects with boolean operation.
Select all the objects, make the base mesh the active object (the biggest one: it's important that this object has at least a piece of volume in common with every sphere object) and choose from BoolTool tool tab the Direct Union tool.

It will take a while (depending on the number of spheres,their resolution and your hardware...for me about 15 minutes), but the result is quite good, clean and, above all, watertight.

Below a view of the insight. Notice how there is only a shell. The internal faces do not exist anymore.

wow thanks man . i give it a try . it sounds perfect . i see you went to some  effort to answer my question . thanks again :)

i had herd the parent vertex duplication called polyverts before yeah . super hand technique for the things i build .

i am having problems with the bool tool . tempramental results on my mesh .
https://i.sstatic.net/UMz13.png
https://i.sstatic.net/yc8Th.png
any ideas ?

I think is better to start a chat discussion about this aspect, join me there! http://chat.stackexchange.com/rooms/26480/complex-internal-vertices

In edit mode select all the outside vertices with the circle select tool (C), make sure that the limit selection to visible button is on. Then hide the selected vertices (H), select all the inside vertices and delete them. ALT + H --. to unhide the outside vertices

thanks but i think the bool tool is the way to go . i dont want to be selecting  all the verts etc . thanks again .


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How to paint vertex alpha in the new version for unity?
https://youtu.be/DMS1I-gJkzE
According to google, making bottom vertecies opaque and top ones transparent should fix the sliding grass issue.
https://www.youtube.com/watch?v=1QbpCZuGe7M
I tried following this tutorial, since blender recently got alpha paint feature, but I cant fix it. I tried making the bottom vertecies black and top white, I tried making top vertecties black and bottom white, I tried top vertecies transparent and bootm full opaque, I tried top vertecies full opaque and bottom vertecies full transparent, I tried top vertecies 1.0 weight and bottom vertecies 0.0 weight, I tried top vertecies 0.0 weight and bottom vertecies 1.0 weight.
Am I using it wrong? When I am painting the alpha, I can see the change in blener , I can see it get more transparent in vertex paint mode, but when I export it to unity, it still slides arround.

Please see this answer.

Are you using the latest 2.79? (if not 2.8)
https://forums.unrealengine.com/development-discussion/content-creation/1513940-blender-2-79c-finally-supports-the-vertex-paint-alpha-channel


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My Diffuse node is broken. Can't change color, as it just gets capped
does anyone know why my blender caps my material color picker? http://prntscr.com/mp0l56 I can't make the color more saturated than this? I can't even color pick, I color picked her dress and it just picks a color no where close to it http://prntscr.com/mp0ksi  Adjusting the brightness of the purple also just desaturates it to white instantly http://prntscr.com/mp0ljd
http://prntscr.com/mp0mzf http://prntscr.com/mp0n3c it just starts curving up to the blue
http://prntscr.com/mp0n8o
and gets capped at .838
http://prntscr.com/mp0nde and if i try to adjust the hue http://prntscr.com/mp0nh7 it just instantly changes the saturation to white
video https://youtu.be/yODr51F2xgo

As mentioned by cegaton, please edit your question to include the images using the tools on the site rather than external links. This makes the question easier to read (as the images are visible) as well as making the question remain meaningful if the images are removed from the external site.
As for your problem, do you have any Blender Add-ons activated that might cause the problem? Does the problem exist in a 'default' fresh Blend file? Do other nodes (eg, Emission Shader) and color pickers also have the same problem?


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Vertices with anything above 0% weight move as if they were 100% weight?
Vertices with anything above 0% weight move as if they were 100% weight?

and as you can see, when the vertices have 100% weight, they move the exact same way

and no, no other bone has any weight on the same vertices

Yes, this is correct behaviour.
The weights associated with bones on a vertex are normalized before the deformation.
A vertex, which is not assigned to any bone vertex group will not move at all. A vertex with two (or more) groups will have its weights normalized. If GroupA and GroupB have weights of 0.4 and 1.6, BoneA and BoneB will the influence the vertex's position by 20% and 80%.
If (as in your case) a vertex only belongs to a single group, that group is "normalized" which results in 100%.


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Limit selection to visible not working?
Limit selection to visible not working?
No matter if i tick it or not, I can't paint through my mesh. http://prntscr.com/muinpy As you can see in this pic, I have it ticked, and the same thing happens if I don't, The vertecies on his belt are still light blue after I try to paint them, since no matter what I do my weight paint won't go through the mesh.

Hi. Please upload images using the built-in uploader. See: https://meta.stackexchange.com/questions/75491/how-to-upload-an-image-to-a-post

perhaps share your file here: https://blend-exchange.giantcowfilms.com/


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How to keep subtitles from imported source
I currently have a video file created with a Contour+ Camera, this records GPS information into the file as two subtitle tracks, however when I attempt to import the file into blender I can see the Video and Audio tracks, but the subtitle tracks are ignored.
Using FFMPEG I get the following details of the file
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'FILE0093.MOV':
  Metadata:
    major_brand     : qt
    minor_version   : 0
    compatible_brands: qt
    creation_time   : 2016-02-14 15:04:01
  Duration: 00:15:33.17, start: 0.000000, bitrate: 11369 kb/s
    Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 11189 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc (default)
    Metadata:
      creation_time   : 2016-02-14 15:04:01
      handler_name    : Ambarella AVC
      encoder         : Ambarella AVC encoder
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 127 kb/s (default)
    Metadata:
      creation_time   : 2016-02-14 15:04:01
      handler_name    : Ambarella AAC
    Stream #0:2(eng): Subtitle: mov_text (text / 0x74786574), 5 kb/s (default)
    Metadata:
      creation_time   : 2016-02-14 15:04:01
      handler_name    : Ambarella EXT
    Stream #0:3(eng): Subtitle: mov_text (text / 0x74786574), 19 kb/s (default)
    Metadata:
      creation_time   : 2016-02-14 15:04:01
      handler_name    : Ambarella EXT

The power of this is obviously when clipping and merging this if I can align the subtitle I will retain the information to enable speed guages etc to be applied later.
Can Blender retain the Subtitles or should I be using something else to edit these videos?
Nick(c)

Blender doesn't have much support for subtitles. Have a look at this addon and this using animation nodes. You would need to use ffmpeg to extract the subtitles as text to import them into blender.

Thanks for that, it's a shame that it's not there, and odd that it's not been needed before. Is there any other Video Editing Tool for Linux that does import existing subtitle tracks?

I know there is openshot, kdenlive and pitivi but I haven't used them to know if they work with subtitles.


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Is it possible to read a ply format file using python code in Blender
I have a ply file .I need to read the vertices, edges etc. It would be nice to read the ply file in blender and I can program further.

In case anyone else lands here from google looking for the answer, in blender 4.0 they removed the old ply loader implementation, now it is called through wm:
bpy.ops.wm.ply_import(filepath="/path/to.ply")

On the up side, as it is now implemented in C++, it is much faster (also same applies for obj files).

Yes and this applies to most/all other formats.
You can:

Call the operator from Python:bpy.ops.import_mesh.ply(filepath="/path/to.ply")
Import the addon module and run the function which is used for importing:See the source code, its not to hard to see how you would call the load function. eg:
from io_mesh_ply import import_ply
import_ply.load_ply("/path/to.ply")

I have an active object in ply format in blender. I need to read ply data of selected surface in mesh. Can you help me with example code. For example I I need the x,y,z coordinates of the selected portion in the ply mesh. .how can I code to get those details.

Please help @ideasman42

@kpdkps, please as a question which goes into some detail about whats needed

I have ply format mesh in edit mode in blender. When I select some vertices , I need the x y z coordinates to be printed as output. Is it possible. @ideasman42

@kpdkps, yes, but better ask a separate question.


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surface area of a mesh using Python code in Blender
How to find the surface area of a complicated mesh using Python code in Blender. The mesh can be  .obj .ply or .stl .

One way is to sum bmesh face.calc_area() for all faces.
import bpy
import bmesh

obj = bpy.context.active_object

bm = bmesh.new()
bm.from_mesh(obj.data)

area = sum(f.calc_area() for f in bm.faces)
print(area)

bm.free()

Will give result in objects local space would need to allow for scale.  eg if the object is scaled by (2, 2, 2) would need to multiple result by 2 x 2.  Or apply scale before calculation.

@ideasman42   I am not getting  any output even though it shows no errors .

Need a blender mesh object selected in object mode. Run script. Output will be printed to the system (not blender python) console.   You will need to import obj, ply or stl models first.

The code from 3D Print Toolbox expands on this example by also accounting for scale, modifiers and the unit settings to give accurate final measurements in either metric or imperial.

Is it possible to find the AREA of a selected portion in  mesh.( or the portion marked by seam/pencil) . It would be more useful than finding the area of actual mesh. @ideaman42

Yes,     To sum the area of selected faces use area = sum(f.calc_area() for f in bm.faces if f.select)   Examples of using bmesh on active edit mesh.  http://blender.stackexchange.com/a/40979/15543  http://blender.stackexchange.com/a/41758/15543


text:
Rendering via python - markers problems
I'm trying to render a timeline (or some specified frames) with a plugin. I set the active camera I want with
context.scene.camera = mycamera

but there are markers in the timeline with different cameras and I end up with the wrong camera rendered.
How can I ignore those markers while rendering or, at least, change them to my intended camera?

A quick easy way without scripting is to use the Outliner to disable render from cameras you do not wish to use.
If you specifically want to do it in script, you'll need to run through all objects of type 'camera' then set the value for those you wish to not to render.
bpy.data.scenes['Scene'].camera.hide_render=True
Render your scene then return the cameras.
Below seems to work fine but be sure to have your camera selected.
import bpy

list_of_all_scenes = bpy.data.scenes

if bpy.data.is_saved:
    for y in list_of_all_scenes:
        bpy.context.screen.scene = y
        selected = bpy.context.selected_objects
        objs = y.objects
        for x in objs:
            if x.type == 'CAMERA':
                x.hide_render = True
        objs.active.hide_render = False


text:
How can i get the change in value of an objects rotation between the current and previous frame, and use it in a driver
I want to use the change in rotation between the current and previous frames to rotate another object.
EG object A was at 30 degrees in Z axis last frame,
and is now at 35 degrees in Z axis on the current frame,
so has changed by +5 degrees,
so i would want object B to rotate by +5 degrees.
How can i get Z rotation value from the previous frame, and use it in a driver?
I have practically no python knowledge but from other similar questions this might be the only way, but i don't understand how to actually make a script work with my driver.

import bpy, copy

#get current frame
thisFrame = bpy.context.scene.frame_current

#go back one frame
bpy.context.scene.frame_set(thisFrame -1)

#get z rotation of current object
print ("rotation on frame")
print (bpy.context.scene.frame_current)
print (bpy.context.object.rotation_euler[2])

#set custom property ZrotLast to be the same as z rotation
last =copy.copy( bpy.context.object.rotation_euler)
bpy.context.object["ZrotLast"] = last[2]

#go back to current frame
bpy.context.scene.frame_set(thisFrame)

#set custom property ZrotCurrent to be the same as z rotation
bpy.context.object["ZrotCurrent"] = bpy.context.object.rotation_euler[2]

#get z rotation of current object
print ("rotation on frame")
print (bpy.context.scene.frame_current)
print (bpy.context.object.rotation_euler[2])

#work out difference between current and last frame
bpy.context.object["ZrotDelta"] = bpy.context.object["ZrotCurrent"] - bpy.context.object["ZrotLast"]

Please note DO NOT try changing bpy.context.scene.frame_current to change the frame! it will appear to work but it seems like nothing in the frame updates so you will get the same rotation information as the original frame, use bpy.context.scene.frame_set and it works correctly.


text:
Recommendation for graphic card
My CPU is Pentium G2020 running on Gigabyte H61M-S2P motherboard with 8GB DDR3 ram.
I want to upgrade for faster rendering without adding additional RAM on my machine or changing the processor.
Please suggest a suitable graphic card.

I'm voting to close this question as off-topic because this is a hardware recommendation

For the record, RAM doesn't affect render times. If you would like to know which graphics card you should buy for rendering, i suggest visiting http://blenchmark.com. Here you have a full list of all the benchmarks on almost all the consumer CPUs and GPUs.
edit: typo


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Black lines appear when rendering!
I don't even get what is happening with the lines how to i get rid of them?

could you upload your blendfile?

I think the problem could be caused by overlapping faces, or objects


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Blender not working in Windows 10, any suggestions?
Yesterday, I upgraded to Windows 10 from Windows 7 and I had Blender version 2.75a installed before the update. Went to load blender and I get that script box that pops up to load blender and then nothing happens. The box does not show anything and then it just closes. Any suggestions?
I have tried reinstalling blender after the update. Same thing happens.

Reinstall C++ 2012 redist here: https://www.microsoft.com/en-us/download/details.aspx?id=30679 might help

I have tried both and still no luck. The Blender-app.exe does the same thing as stated above (opens the script box). I also reinstalled the C++ Redist, no dice. . Thanks for the suggestions. Anything else come to mind?

related http://blender.stackexchange.com/questions/34901/does-blender-work-in-windows-10

Probably the best thing to do is to wait for blender to come out with a compatibility update. If you're a major blender user, I'd refrain from updating to windows 10.

I've been using Blender one Windows 10 for a while and have not had any problems.
Some tips:

Run the latest version
Run as Administrator
Try the installer instead of the zip, or the zip instead of the installer


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How can I tear two bones and their skinned mesh apart during animation?
I'm trying to create a stylized version of the black knight sketch from the movie Monty Python and the Holy Grail. Two characters are engaged in a sword fight, with one of them ultimately loosing a few limbs.
I set up a prototype character, rigged and skinned it and got to the point where I need to tear two bones of the armature (including the mesh) apart, which is causing me a bit of a problem.
I already tried to set up the parent-child relationship between the two bones that need to be seperated by using a modifier and decreasing its influence to 0 during animation. But this still leaves me with the weird deformation of those vertices skinned to the seperated bone.
Another idea might be to use different versions of the character model and swap them during animation. But first I'd like to ask if there is a less time-consuming option?

If you wanna tear a bone chain in a specific joint, you can't just break the parenting of those bones, as this will break the skinning as you noticed.
You need 2 chains to overlap in the location of the tearing (exaggerated with a gap):

The amount of overlapping depends on how your bone weights overlap on the mesh.
You skin the bottom piece to the green armature and the top piece to the red one. To tear the limbs/parts apart you just separate the armatures.
The only problem is mesh smoothing in the area of tearing. You can fix that with normal mapping or with custom split normals that blender now supports.

Thanks, this worked for me.
Just one additional question: How did you color the bones like that?

@Neovertex I've put them into bone groups and color the bone groups with a color theme. Then I overlayed the images like that in photoshop.


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Why does my mesh deform when I apply an armature with automatic weights?
Im quite new at rigging so I was following a video tutorial and everything seemed to be great until i applied the armature to my model. When I applied the armature with automatic weights the entire mesh deformed and I tried rotating bones but it made the bones bend incorrectly and weird and deform the mesh even more.
Just some help for a beginner would be fantastic and an answer in a way i can understand, i just want to be able to animate him for a project i have.Oh and if you want to download the file here is the link (and the save starts before adding the armature in):
https://mega.co.nz/#!4ZVgEIbR!9XwuFm5_mOtRP3ImUnwGxSsoQ3zIArLqiV0erQ0iI_k

I have to say i'm not really good at rigging, but as none answered...
there are a few things you need to know about armatures and bone constraints.
Your armature won't look the same in edit mode and in pose mode if you apply IK contraints. Edit mode allows to move/rotate/scale bones in rest pose so if your bones are moved in pose mode, this won't show in edit mode. Constraints are not applied in edit mode.
This applies to your IK controller bones.

So if you want to see things clearly, you have to clear the tranformations in pose mode : select all bones with A menu Pose/clear transforms/all or Alt+G, Alt+R, Alt+S.

Another thing to know about bones is the roll, the bone's rotation around it's main axis. To see this, go in properties panel, armature and click "Axes"

This wil show each bone's axes. This is something you need to check if you want your contraints to work as expected. You can change a bone roll with Ctrl+R in edit mode. In your case, you should use the recalculate option : in edit mode, select all bones with A, go to armature menu, Bone Roll/Recalculate Roll/Global+Y axis and see what it does.

It should fix some of your problems but you'll need to manually fix some of them. You can try some recalculate options to see what's best


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UV Texture Looks Wrong in Render
I've been learning how to use UV mapping with textures in Blender. Things have worked fine so far using simple shapes like cubes and cylinders, but everything went wrong when I tried to UV map a creature mesh. It looks how I'd expect in 3D View: brown with a lighter color on its belly. However, the render is all messed up.
Comparison with 3D view on left and render on right:

The creature's properties:

Kallenboone, welcome to the site. If you would upload your ~.blend file to Blend-exchange or a similar site so that those who would wish to help you could see your actual file, that would be more useful than the edited screen shot you provided.

Do you have a subdivision modifier on the model?

@brasshat Thanks for the tip! I couldn't find a way to upload my files here, but I put them up in my public Dropbox folder.
Blend file: https://dl.dropboxusercontent.com/u/28277866/creature.blend
Texture: https://dl.dropboxusercontent.com/u/28277866/creature.png

@Denis I do indeed. The texture is still messed up if I turn off the subdivision modifier, though.

Nothing is wrong with your UV set up. It looked fine when i opened it. I didn't change anything in your blendfile, except for the lighting. I put 2 sun lamps in the scene near the camera and pointed it at the object. And deleted the 3 lamps you added.

@kallenboone the problem is in the light because you applied the creature's texture on 2 of them

That fixed it. Thanks for the help! I didn't even know it was possible to have a texture on a lamp like that. The next part of the guide I'm following is all about lighting, though, so that should be enlightening.


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Force 3D View to Redraw?
I've written a pair of functions for exporting the currently selected indicies to a file, then reimporting them.
There's no particular reason for this other than to get more comfortable with writing scripts for Blender.
Here's what I have:
import bmesh
import bpy
import json

def exportSelectedIndicies(filename):
    mesh = bmesh.from_edit_mesh(bpy.context.active_object.data)
    selectedIndicies = [i.index for i in mesh.verts if i.select]
    with open(filename, 'w') as f:
        json.dump(selectedIndicies, f)

def importSelectedIndicies(filename):
    mesh = bmesh.from_edit_mesh(bpy.context.active_object.data)
    with open(filename) as f:
        selectedIndicies = json.load(f)

    for i in mesh.verts:
        i.select = i.index in selectedIndicies

    mesh.select_flush_mode()

The export portion does exactly what I want. I'm happy with it.
The import portion doesn't seem to do anything when you run it at first. It's not until you click away from the console and into the 3D View that it suddenly updates your selection.
It seems to me that the import portion is just missing a little part to tell the 3D View that it needs to redraw itself. I searched around online and found some stuff saying that there's a Blender.Redraw method that can be used, but there's no such module Blender or Redraw that I can import. I suspect that either those functions aren't exposed to the Python API, or they're from an older version of Blender and have since been deprecated.
I see that I can access the SpaceView3D object, but it doesn't seem to have any redraw method that I can use.
So what am I missing here? Is there some kind of flush, mark_dirty, draw, refresh, or redraw method that needs to be called for it to trigger that it needs to be redrawn (and on what object, and how would I get at that object?)
Is this a bug? I am using version 2.74... do newer versions have the bug fixed? On that note, do newer versions add in a function that I need (I just haven't updated because I don't use Blender much, and because my network is slow so updating takes several hours. But I'll go ahead and update if that'll fix my problems.)
If it is a bug or something that's been overlooked... is there a workaround I can use? Maybe something to emulate clicking on the 3D View, then clicking back on the Console (so I can enter more commands afterwards...)?

At a first glance you can try: bmesh.update_edit_mesh(mesh) and scene.update(), related: http://blender.stackexchange.com/questions/414/how-to-use-bmesh-to-add-verts-faces-and-edges-to-existing-geometry

@poor - Actually, I was using bmesh.update_edit_mesh(mesh) incorrectly! I just realized bmesh is supposed to be the module itself, not an instance of the BMesh class. So just adding this line worked for me: bmesh.update_edit_mesh(bpy.context.active_object.data). Add an answer saying that and I'll mark it as correct. Thanks!

@poor - I had actually seen that question/answer before asking my own. Because I had used bmesh.update_edit_mesh(mesh) with the incorrect arguments though, it didn't work for me.  So I've proposed an edit to the answer with some notes to hopefully clarify the arguments that should be used with that function. Also, since my question was about changes in selection, not geometry, I thought maybe mine would have an unrelated solution.


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Blender freezing when I try to add automatic weights to a parent?
still very new to Blender, and I was following this tutorial for creating rigging to a character model.
At around the 10:12 mark, we're instructed to hit Crtl+P while selecting both the armature & the mesh, and clicking on "Set Parent to...Armature Deform...with Automatic Weights". Upon doing this, my software immediately freezes, and I can no longer continue the project. Considering the fact I have a really nice setup, I don't think it's my video card persay, I'm curious what's causing Blender to freeze up. I'm not sure how I can continue from here. (The screenshot is my current model, where I'm trying to apply the step explained)

So, what am I doing wrong? Is my current character model too complex? I noticed the leg bones stick out of the leg mesh slightly, is that the problem? Or did I miss something else entirely?
Thanks so much for your help!

870000 vertices, your mesh is very high poly, this makes blender freeze

In your screenshot it looks like only the armature is selected. That said, that shouldn't cause blender to freeze.. If your mesh has a lot of polygons, blender may take a while to compute the weights, which will make blender appear frozen until the process is complete. How long have you waited to see if blender unfreezes? Ideally you would weight a lower-poly model, then use a subsurf modifier after the armature modifier to increase the resolution.

authors: Николай Пильчук


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How do I make it so something will go when collected, then re-spawn after awhile?
So in Game Engine, I have been trying to make an empty that after a message gets sent, AND after 30 seconds, the object will come back, but as I can see, the message only sends once, and the logic brick does not remember it being sent, so after 30 seconds, the message isn't there. Is there any better ways to do this, or any way to make the message sensor remember that it has been sent
The message is for, when it gets deleted, it gets sent to an empty to spawn there, but I want it after 30 seconds

I think you can go with the same solution as asked in How to limit the frequency of pushing of keys in the BGE? It is a timing issue too.

You can toggle objects.

On request the visible object can remove itself and adds another invisible object that counts the 60s.

After timeout the invisible object deletes itself and adds the visible object again.

As you can only add objects from an invisible layer and you want to re-add your objects, I suggest to start with an empty that immediately adds the visible object. This "startup" empty is not needed anymore and can end itself too.

ok, so this has worked, however, each time the item comes back, it is smaller than the last

This is because your objects scale is screwy, select both the object you want to spawn, and the invisible spawner object and [ctrl]+[a] > scale. that should solve everything.

Ah.. Thank you, it's working perfectly fine now


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Way to use large textures in Blender without crashing?
I've downloaded the largest size of the Blue Marble Next Generation textures from NASA. I was hoping to be able to do nice closeups of an earth scene, as well as good real displacement, but Blender crashes immediately upon opening large textures. Are there any way to use larger texures (32K and up?)
Thanks!

This question appears to be off-topic, as bug reports are considered off-topic on Blender.SE. If you have found a bug, consider reporting it on the bug tracker

This is a stretch but you could perhaps check to see if you have the texture size limited in your user prefs under Settings

It's most likely you system is just running out of memory. Please include a link to said image so others can test (a quick search only resulted in smaller or multi Gigabyte images).

I just tested it with no crashes (though it's extremely laggy) with the last image (21600x21600) on this page

Do you really need an image that big? If it's causing Blender to crash, just scale it down in an image editor and load it in again. Most of the time that's a hardware issue (not an issue with Blender itself).

Unfortunately we are limited by the amount of RAM our computers have. A 21600x21600 image (at 8 bits per pixel and with RGB channels) takes up around 1.3 GB of RAM. Combined with geometry and other programs, this may be more than your GPU can handle.
How I understand it, the GPU, which has it's own set of RAM, is used to draw the blender interface and all the models - but the CPU is used to render the image (unless you specify to use GPU rendering) which uses your main system RAM. So it may be possible to setup the scene without actually trying to view the image in Blender, then render it (possibly from the command line) to ensure the image never loads into the GPU RAM.
However, this might not be enough.
A common method of zooming into something and seeing a high res texture in the animation is to use a bunch of layers:

This is an exaggerated example of course, but the parts of the image you won't ever see in high-detail don't need to be high-res. Cutting up the final image and lowering its resolution for each layer, cropping the high-res ones to show only what you need, will save a lot of memory.
To hide the seam better, use more layers with less of a change in resolution, or create an alpha mask to fade out each layer on the edges.


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Masking geometry without breaking constraints/parents
It is common to use simple geometry for physics simulations, and then parent more advanced geometry to it to be rendered. Normally this simple geometry is on another layer. However, I have a case where the simmed geometry is on the main render layer and part of an object that needs to be rendered (because it's all one piece brought in with a mesh cache.) Separating any verts out isn't an option as it would break the cache.
I need to mask out some of this geometry, but I have empties parented to it and bones constrained to it as part of my rig. If I use the mask modifier, these break as the vertices are missing. I can put a transparent shader on it, but this still costs render time and produces artifacts at intersection.
Is there any other way I can get these verts to not render?

If you are using cycle ...
You can turn off certain types of ray visibility for individual objects and the camera will ignore them.
NOTE
If this question is more complex than it seems I advice you to upload more images and even a portion of the .blend file so someone could download and dissect the problem.

The issue is that I need to hide some parts of the geometry within an object, but not other parts.


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Change editor tab with a hotkey?
Are there hotkeys for changing between the tabs in the 3D view Toolshelf (Tool, Create, Relations, etc), or is it possible to create them?

You could scroll them with LMB however cursor should be over the tabs. If you need particular rollout in every tab you could Shift click its name.

I am not sure, but I don't think that is currently possible, at least not without some scripting involved. But then again you seem to want to streamline or speedup your workflow, if you are going to bother creating or memorizing hotkeys for tabs why not got the full length do it directly for the tools you will be using instead. They most likely already exist and will probably be much faster that tab switching and pressing another button.

I agree with the guys above. Pin all of the tabs (Shift+LMB, while hovering the cursor over the panel's name) and make a long list. Pinning tutorial is here: https://www.youtube.com/watch?v=h1ik0rlJuK4


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Interlace video frames
I want to concatenate several video files into one. Say I have 4 files. I want the new video's first frame to be frame 1 of video 1, 2nd frame be frame 1 of video 2, 3rd frame to be frame 1 of video 3, etc, and then looping. Is there any way to do this, preferably in the compositor?


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Do rays fire if you have no materials of their type?
If you have no transmission materials, does Cycles still process transmission rays? Is there any speed increase to disabling a ray type if you don't have any materials that use it?

By definition you need transmissive objects in order to have transmission rays, so AFAIK no.

Are you talking about branched path tracing?


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Randomizing crowd scenes with instanced models
I want to set up a crowd scene using instanced models with a lot of randomization. Say I have a library that consists of several bodies, hairstyles, and outfit pieces. I want to make a crowd where each member has their pieces randomly drawn from this library, as well as random colors in their materials, but also drawn from a list or predefined colors. And then have a random pose from a pose library, but still each have their own rig intact so that their individual poses can be changed/tweaked. And i want to do it all without breaking instancing to the original models, so that if any of the assets are updated, all of the members of the crowd using those pieces will get the update.
Is this possible, and what is the best workflow for it?

My hammer is python, and your problem looks like a nail.  I would develop python that can instantiate copies of the bodies and hairpieces at the proper locations (http://web.purplefrog.com/~thoth/blender/python-cookbook/link-mesh-array.html illustrates the basics of this technique).
Linking meshes with armatures is done with modifiers like in http://web.purplefrog.com/~thoth/blender/python-cookbook/bone-orientation-demo.html (which also includes examples of adjusting the orientation of bones).
A python solution to your problem is somewhat involved, but I am optimistic that there are examples of all the techniques you need somewhere on stackexchange or google.


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Can electricity be simulated in Blender?
Can static or dynamic electricity and the electrical interaction among current-carrying wires be simulated in Blender?


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Can Blender use the open-source Nouveau Nvidia driver for rendering?
Can Blender use the open-source Nouveau Nvidia driver for rendering, or must I use Nvidia's proprietary driver?

@cegaton Why? Nouveau can't do 3D / OpenGL?

@cegaton Is there not an open-source implementation that could?


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Using Python to add object with specified number of vertices?
How, in Python, could I add an object with a specified number of vertices n, all of which are at, say, the origin (0,0,0)?

Related http://blender.stackexchange.com/questions/414/how-to-use-bmesh-to-add-verts-faces-and-edges-to-existing-geometry?rq=1 http://blender.stackexchange.com/questions/2407/how-to-create-a-mesh-programmatically-without-bmesh/2416#2416

To do this:

Press Shift+C to position your cursor at the origin (0,0,0)
Follow this answer to create a mesh with a certain number of vertices


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How to mask an imported image as a plane in Blender 2.8?
I have the following scene in Blender 2.8:

I imported the Blender logo as a plane (File > Import > Images as Planes ---which is a plugin---).
I want to create a rectangular mask on the Blender logo to hide part of it, so I do the following:

To apply the mask to the image, I UV unwrap it first:

and then I go to the shader editor to apply a mask node to the plane containing the logo. But I cannot find such a node!:

If I render, I get the logo without the mask:

How can I apply the mask to the image?


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Allow Blender Matierals to Reflect Ambient Light Color
I'm trying to light a scene in blender. I have set the diffuse color but want it to reflect ambient light as well. When I turn up the ambient light reflection and turn up the scene ambient light, the object reflects the ambient light but reflects white light instead of the green light I want it to. Its produces a washed out effect. How do you light it so the dark part of the sphere reflects a little green from the ambient light and the bright spot reflects the green from both the ambient light and the diffuse light.

Often times using ambient light will produce a washed out effect.  You may want to consider using the world color instead of the ambient.

Are you using BI or cycles?

I'm using cycles right now. I am using it to create a learning database for some inverse rendering machine learning algorithm according to the Phong reflection model and am trying to light the same scene with ambient light, ambient & diffuse, and ambient & diffuse & specular


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How to restrict to cycles use only 90% of gpu?
How to restrict to cycles use only 90% of gpu? For example redshift use always between 80-90% and because of that i can work with something else when render on video card. But when i put render on cycles i can forgot about using PC while rendering.

Apparently my rep is too low for a comment. Which I would have prefered to do. As this is something of a duplicate question. The limiting process is explained here.

From the Blende manual on GPU Rendering

Why is Blender unresponsive during rendering?
While a graphics card is
  rendering, it can not redraw the user interface, which makes Blender
  unresponsive. We attempt to avoid this problem by giving back control
  over the GPU as often as possible, but a completely smooth interaction
  can’t be guaranteed, especially on heavy scenes. This is a limitation
  of graphics cards for which no true solution exists, though we might
  be able to improve this somewhat in the future.
If possible, it is best to install more than one GPU, using one for display and the other(s) for rendering.

i consider - if others gpu renders can be responsive (in my example redshift in maya - while redshift ipr rendering maya fully functional) during rendering then in blender must be some options....well if so in cycles then i will hope developers add this (in redshift for example devs somehow control gpu usage in 80-90% load) in future...


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Is it possible to "pack" a .mdd mesh cache animation into the .blend?
I've successfully loaded a mesh cache .mdd file to create an animated mesh. However, if I choose File > External Data > Pack All Into .blend the mesh sequence does not seem to get baked in.
Alternatively if I click "Apply" in the Add Modifier > Mesh Cache, I only get the mesh deformation for the selected frame applied to all frames of the animation.
How can I pack the .mdd mesh cache animation into the .blend?

You can pack all sorts of file formats into Blender by adding an Empty-->image, and  selecting the file to be packed.  From there click in the pack-file slot immediately below.  The only formats I've noted that it won't accept are video formats. Their extensions have to be changed to non video, or zip the file, then pack it.  Note that apart from pic files, this method of packing is just that. It saves the file inside the Blend file but has to be recovered (and renamed?) manually.

Do I understand correctly that this means that the data is technically in the .blend but to actually use it I'll have to extract it into a file upon opening? (If so, this is not what I'd like to do. I'd like to pack it the same way textures, environment map images and mesh assets can be packed).

Unfortunately, this would possibly be the case with the file type you're trying to embed.  It was suggested as a next-best solution, handy for keeping necessary components together, not scattered about the computer or even getting lost.


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Possible to convert tangent-space normal map to object-space normal map, given obj + png?
I have a 3d model as a .obj (with uv coordinates) and a tangent-space normal map as a .png.
Is it possible in Blender (using just this information as input) to write out a object-space normal as a .png?
Here's an example.
Given this 3d model of a head as an .obj and this tangent space/local/relative normal map:

I'd like to be able to bake out a object-space/global/world normal map like this:

Maybe use the bake settings discussed here: https://blender.stackexchange.com/questions/72663/how-to-bake-a-bent-map-object-space-normal-correctly-with-cycles


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Why does parenting handle bones differently than the Child of constraint?
When an object is parented to an armature's bone it's center is originated at the bones tip, which for some reason is called tail... (that part is never gonna make sense to me but whatever)
But when you use the Child of constraint it will be originated at the bone's root.

Here's an image showing one bone, 2 icospheres, neither has been moved at all.
Icosphere.001 is parented to the bone, the panel on the right shows it's info.
Icosphere is Child of constrained to the same bone, shown on the left and in the center.
The only thing they share is the rotation and scale, but the location is obviously different, for whatever reason.
Why is this like that?


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How to align two vertices on two planes?

I have 3 vertices here which I try to align, the bigger User Orth view looks down along the 2 which already are aligned over each other.
The upper left view shows a sideview and the arrow represents the axis at which the big view is looking down along.
I'm trying to get the selected vertex inline with the 2 behind it, the problem is that I need to restrain it on 2 different axis which are in different orientation spaces:
The main orientation is the big view's camera, 30deg down along that edge.
But my problem is that I also need to prevent the vertex from changing it's global z because I want the top surface to stay flat.
What I've managed so far was using vertex snapping with the big view's transform space set to view and locking view z to snap it inline.
That'd work fine if it wouldn't still mess with the global z slightly anyways.
So is there any way to align that vertex with the ones behind it but keep that top surface flat?

While in the bigger User Ortho view, select the vertex you want to move, the one that cannot be moved in the Z axis. Once selected hit G, then Shift+Z (this allows the vertex to move in the X and Y axes, but not the Z axis). Then, holding Shift to limit movement speed and increase accuracy, visually line up the vertices. While not mathematically exact, you can zoom up quite close to ensure they are aligned to your liking.

Yeah, I tried that, and for people without OCD would this be perfectly fine, but just knowing that it's not exact is irritating the hell out of me so I'd prefer a method that puts them exactly inline : (
As for the zooming, that's actually not as easy because the screenshot shows the maximum it will let me zoom in in ortho.
No idea why but it limits me there extremely quickly.


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Background environment texture not rendered in viewport or final render
How do i make this visible?.
Every tutorial I see, it is automatic. But my scene is not mine, aparently they made it invisible, but I want to see how it is positioned and I need it to be displayed in the viewport with rendered option on.

Please provide more details to your question and attach the blend file if you can.

What is displayed instead of the background? Do you have transparent film enabled? Related: http://blender.stackexchange.com/q/14219/599

I can't post the file here, it's private content. I just render, and the environment texture set is not displayed when i render with Cycles. But the effects of it over the specular are visible. I just want to position the environment. In the examples I've seen in tutorials, it is available and can be seen

gandalf3, nothing is displayed. It's black. What is a transparent film?

Go to Render Properties tab under Film and deselect Transparency, only works for Cycles.

You also need to turn on Use Nodes just under your image

In my case, I had my Clip Start at 0.001, which prevented anything in the background from showing. After zooming out a bit, the environment texture reappeared.

Your environment is disabled.
Check your scene settings, "use environment".

This is a 3y old question! But anyway, try to detail more what could solve this... I could not get what you meant.


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Center viewport key in Blender breaks the viewport
I set the key layout to Maya's to work faster, everything goes great.
But when using F key (i don't remember which one is in blender, but the center viewport position and rotation to selected object).
Then everything goes wrong. I'm not able to get near the object. The position where the camera gets centered is another , far from the object. Their pivot point is where i want to look, but the vew goes away, and moving is a nightmare.
Moreover, when trying to approach the object i wanted to center on, the camera gets slower and slower (as in Maya) but I'm not able to get there...
Is there a bug or something? What do you suggest me todo, instead? but not turning to blender layout, please. :-)

You are asking multiple questions, one of which I think is answered here: http://blender.stackexchange.com/questions/644/why-does-the-zoom-sometimes-stop-at-a-point .

press A to select all objects in your scene, then press numpad period.

X-27, this is not like that in Maya layout.

I had this problem like this early on.  It's because you're in perspective instead of ortho mode and in perspective the viewport behaves differently, it never goes in close to the object you're zooming, in ortho mode this doesn't happen.  Perhaps I'm over simplifying; but it behaves as you're saying on the 'when I move closer, I don't get any closer" I don't know about Maya.  If this is the issue, simply hit the number '5' on the number keypad in Blender key layout to switch between Ortho and Perspective, you want Ortho. if User Preferences are organized the same in Maya as in Blender, this would be under user settings: Input/3D View/3D View (Global)/View Persp/Ortho if you need to change user settings for Maya, or see what they are.

related: http://blender.stackexchange.com/questions/644/why-does-the-zoom-sometimes-stop-at-a-point

Nope. That's not the problem, but useful though  :-)

I found the answer.
I tried to change to "walk mode" , which turns camera to a FPS game - like movement style. It said I couldn't change because my cam was locked to an object.
In fact, it was locked to the camera, so no matter where I centered the view, anything i did made it go towards that camera. So when using the wheel, it didn't go forward... but to the side (??) : It was moving towards the camera to which the view was locked to.
Funny. I did that while trying to move the camera together with the view... forgot to turn it off again :-D


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Lighting on triangles - every other one is darkish
I have a mesh in Blender, imported from elsewhere. You can see individual triangles on it in a funny checkered pattern, like this:

This is consistent with a popular bug where every other triangle is inverted, and you see half of them from the inside and half from the outside. But if you enable normal display, all the normals are facing outwards, as expected.
The mesh is available at http://www.jishop.com/temp/4osh.blend . Can someone please take a look at it explain the effect?

Seva, might you be willing to upload a copy of the ~.blend file you linked to in your question to Blend-exchange, and change the link? The reason for this request is that your question and the screenshot will persist for some time, but I fear that a file located on a page whose URL contains "/temp/" may not last as long as the question. The question is more valuable to future Blenderheads with your ~.blend file.

I entered Edit mode, pressed the Spacebar and typed the tool name "Tris To Quads".  The model looks fine after that.  It's usually a good idea to avoid triangulation unless you are exporting a finished model to a game engine.

@MarcClintDion I didn't know there's a tris to quads function! I have to ask though, why are you posting this as a comment?

@brasshat: that's my site :) Temp or not, it'll stay for a while.

It's a nice tool because it has an undocumented alternate function.  You can import a triangulated model and if Tris To Quads fails then you know that area needs some repair.  If this tools fails then that area of the model will likely cause animation and rendering errors.  It basically finds mistakes in loop flow that a person might not easily see ahead of time. :)

The triangles are all being displayed in 'Shade Flat' mode, which is the default. To change this, go to edit mode and select all faces (hit 'A' once or twice, until all triangles are selected). Then Hit 'W' then select 'Shade Smooth'
[Shade Flat] mode is appropriate for modeling a faceted gemstone, or cut crystal glass, for example. Since blender cannot know ahead of time what type of shading you need, it defaults to 'Shade Flat'.

Shade smooth is for hard edges with low topology, and us good for modeling at an earlier stage (most of the time it's easier to see what's going on with sharp edges). Smooth shading is best for higher topology objects where you can see the edges, or smooth parts of low poly models. I'm pointing this out, because I don't think shade smooth is good with the examples you provided. I find that it's usually best to set the shading in object mode (because it does it globally). I've had issues with having some faces set to one type of shading, but something else in object mode. This could just be me.

I rearranged my answer after posting, not realizing that the clause 'This mode...' was now seemingly referring to 'Shade Flat' instead of the intended 'Shade Smooth'. Thanks for making this clear. (edited my answer to fix this)

This helped; the mesh looks, well, smooth :) What's the theory behind this, please? Is it a property of the mesh or a rendering setting?

@brasshat: that'

The difference between flat and smooth shading is the calculation of surface normals. In flat shading, all three (or four, or x) vertices in a face share the same surface normal. In smooth shading, a face will have (or may have) different surface normals for each vertex. As surface normals are computed from the underlying mesh, it might be said that it is a property of the mesh. But it is a render-setting that determines whether blender uses face normals (flat shading) or vertex normals (smooth shading).


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Dimension for UV unwrap
I get a problem with UV mapping in Blender.
I do some render of architecture, and I get some walls of 2.25m height and 10m length.
So I did a picture of 1024px x 3072px to get a good resolution.
But when I unwrap (solid, cube, from view, etc), proportions are not good... (and I reset scale object to 1 before unwrapping).
It seems that if picture is 1024 x 1024px or 2048 x 2048, I don't get this problem.
Does someone can explain me the problem (and any solution?)  :-)
Thanks in advance and best regards!

use "Project from view (Bounds)"  to get UVmap of the same size as the image


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Is there an Edge Crease tool for the Smooth option (similar to that used for the Sub surf modifier)
I know this is a long shot (and I'm going to have to go back and delete/recreate my arrays with a subsurf mod) but since I've already locked in most of them:
I was wondering if there is a tool that acts as an Edge Crease (for the smooth option) that'll allow me to sharpen up some of the edges on a tire.
Currently my rendered tire looks like this:

When smoothing things definitely get a little TOO smooth.

In the end, I'm ok if there's not, just hoping to save some time :)

Related - http://blender.stackexchange.com/questions/734/how-to-smooth-shade-an-object-while-retaining-hard-edges; also http://blender.stackexchange.com/questions/6425/keep-sharp-edges-when-using-subdivision-surface

Are you interested in a linear intepolation of the shading or just making hard edge? E.g. Edge crease range is -1;1. while Mark Sharp is a boolean variable.

Edge Split modifier may be the thing you are looking for?
After applying the modifier to the object you could use "Mark sharp"
to further modify the behavior of the modifier.
Hope it helps.


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Animating a masked sphere with "star" particles
I'm trying to create a "Stars" effect by adding ico sphere's to a UV sphere as an emission object particle, then rotating the sphere to simulate the passing of time in my animation.

Only problem is, I am not sure how I'm supposed to bake this object/group of objects for animation.
When I convert the particle system the "stars" separate into their own objects, lose their rotational pathing, and just remain stationary. Is there a way to convert this object into separate particles without losing the rotation data, or possibly animate the un-converted sphere object?

Why do you want to convert the stars at all?  What is your final product?

Appended Answer Here:
For understanding's sake, I am trying to recreate what you have done.
You basically had a sphere with random emitted "star-mesh objects".
That Sphere had key-framed rotation information within it.
Then you did something like the following:

Select your emission mesh (where the star particles are being emitted from).
Go to the Modifiers Tab within the Properties Panel.
Apply the Particle Modifier.

???
If this is correct, then what you would probably want to do is add an empty object at the center of the original sphere's rotation.
Select Your Empty.
Hold Shift and select your sphere.
Next: Ctrl + L >> Animation Data. This will copy the key-framed rotation.
Now you can apply the Particle Modifier, to make all of your stars individual objects.
Next Parent these to your Empty.

Not a direct answer to your question but instead of turning the particles into objects you might be even better off by turning them into an HDRi image and then use that as a world texture (e.g. see Create HDR map from render?). You can then animate (i.e. rotate) that HDRi via a mapping node.
Note that this technique might not be entirely ideal if your final animation contains a lot of sideways camera movement. Then again, from your screenshot it looks like all the particles might have the same distance from the center of your sphere. In that case it probably won't make a difference after all.

That's a good idea, though I've got that purplish sheet behind my island and that's my "sky" per-se so the HDRI thing isn't currently viable haha.

Well, couldn't you bake that sheet into the HDRi as well?

Possibly. I'm pretty new to blender, so I wouldn't know how.

See the question and answers I linked to (especially the answer by gandalf3 which also has screenshots of how to set up the environment texture with a mapping node). Just hide everything that is not background (i.e. leave the particles and the sky sheet) and then render out to HDRi as described there. Then hide (or even delete) the background objects and set up the new environment map.

Awesome! Thank you very much Oliver, I'll check it out.


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How do I update textures in the viewport from the textures properties?
So when I set my texture up with UV and change a value such as Blue on the texture properties, my texture stays the same. I looked in the UV Editor and my texture is the same, is there a way to update my UV Editor Image live by changing a property in the texture properties area?
EX: Change blue in the texture area and the UV texture turns less blue than before

There are many unclear details in your question. What render engine do you use? What is that "texture properties / area" where you change "value to blue"? Consider adding more info, screenshots and possibly a .blend file

As you can see, when you change the parameters of the texture's colors, the texture doesn't change: it changes the way the texture is rendered: in the properties window you have the preview tab for monitoring the process. Another way is to choose the "Rendered" viewport shading in the header of the 3D Window.


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How can I import Gerber DXF pattern into blender?
I have DXF files from Gerber which I want to import in Blender for 3D simulation. How can I do that?

In the info bar at the top left hand of the blender program try 'file', then 'import' the find AutoCAD DXF.
try it and keep me posted.

let me know if that option is availible, because if it is not, you might have to turn on a plugin to active this option.

Yup some else had the same issue, you can active this option though Add-ons found in the user preferences section. link to answer http://blender.stackexchange.com/questions/30788/how-do-i-import-a-dxf


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load maps instead of scenes Blender GE
i'm creating a fps game and i was wondering, which is the best way to load a new map without put the player manually in this map? everytime i'll have to create a scene and put my player in there? there isn't a way to creat a blend file for each map and make the main scene load it putting the player automatically in this map?
Sorry about my bad english

Don't you think that the scene the best place to place your player in? How should the BGE know where to place the player object, or even know what it is? Btw. you do no need to copy the player. You can link it. You can even link from other blend files.


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Check which types of physics are used in the complete scene/blendfile
How I can I see which physics (rigid body, fluid, smoke, paint, soft body etc) are used in the complete scene/blendfile, without having to check for each mesh individually? Thanks :)


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Putting transparent image on curved surface with specific placement (UV)
I'm very new to Blender, so please bear with me with this (hopefully) easy to answer question. :) Just to get this cleared: I searched for a total of 4 hours to find a solution to this problem, but I couldn't find any!

As you can see in the picture, I was trying to create a model of a blimp, which worked fine so far.
Now I'm trying to put a text on the front part of the airship, about at the location of the selected faces (see picture). I'm not able to use the normal text tool in Blender, because the text is a logo which I can't recreate using the keyboard.
All I want to do now is put the text on the said surface (and ONLY there, not wrapped around the entire ship) but in a realistic way, as if somebody put a sticker on it (the text should bend with the curve of the hull).
Ideally, I'd be able to move around the picture on the surface until it sits perfectly where I want it.
I'm using Cycles Render because thats what the guy in the tutorials used that I followed on YouTube.
Thanks a lot for any help! :)

related: http://blender.stackexchange.com/questions/1258/cycles-option-to-turn-off-texture-tiling and http://blender.stackexchange.com/questions/19039/how-do-you-overlay-an-image-on-a-shader-in-cycles

Does your Blimp have a texture or a colour?

@IgorTatarnikov So far I only applied a material to it, I haven't touched the texture section. From what I've understood so far, I'll have to use these "nodes", but I have no idea how that works

You have to go to your node set up of your material for your blimp and add a Mix RGB node in which you will plug your transparent texture in the bottom color and the alpha of your texture to the factor of the Mix RGB node. Your color for the whole blimp should go to the upper color, finally you plug the Mix RGB node to your Diffuse node and then to your Material Output/Surface. *Don't Forget to unwrap the part of the blimp you want your transparent texture to be assigned.

p.s. if you want to have textures insted of colors you will have to create a second UV map, *don't forget to give your texture node the right UV map.

For more information I can recommend you this tutorial: *the blender version is quite old but the process is the same:
https://www.youtube.com/watch?v=dnmovLzKU44

It almost worked! (Thanks so far!) Here's however what it looks like right now: http://imgur.com/VZtUVS6 As you can see, the image is repeated and distorted (and part of it is cut off). Is there any way I can make it appear in it's original proportions?

You can go to your UV window and Position/Scale your UVs on X or Y axis, also you can try to project from view

Okay that worked pretty good, the only problem I'm left with is the fact that the image is repeated. So, no matter how I scale it in the UV screen, there's always parts of the repeated image showing to the left and right ...

If you dont have to assign any textures to the left and to the right then you can just make sure these parts are separated by at least one loop cut from the place you need a texture, and just scale the parts (you don't need to have texture on) X = 0 and Y = 0 (in the UV window) and then drag them to the alpha part of the texture, this way they will not be able to display anything. (make sure you place the parts on alpha place of the texture)

You might want to use two different materials.  One material is for the plain blimp and uses the first UV map.  The second material is for the text area and is almost identical to the plain blimp material.  Its difference is that is has a second texture that uses the text-only UV map (each texture in a single material can use a different UV map)


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Iterate through objects then parent and add material based on string search in names
I've imported a model from the BodyParts3D database (http://lifesciencedb.jp/bp3d/)
It's made up of a huge number of .obj files. These have a name based on the anatomical structure/organ:

My question is whether it's possible to use a Python script to go through the objects in the scene and;

parent them together under an empty transform, according to a text string search
add a material based on that text string

e.g. FJ2574_BP48954_FMA14964_Proximal part of ileum.obj
so any object with 'FMA14964' in its name would be parented under a transform named 'FMA14964', and be given the same material ('FMA14964_mat', or whatever).
For #2, I've found this 'How to assign a new material to an object in the scene from Python?' which I could probably work out how to tweak to do what I need, but I don't know how to iterate through the objects in the scene and do a a search based on a text string
I'm new to Python, but ok in C# and other programming languages. Fairly new to Blender (mostly I work in Unity) Any help would be very much appreciated!

Use string.split.
As you are already familiar with programming, and without a test file, will run thru an example. Use pythons String.split to split the name as is into a list using the underscore as a separator.  If there are 4 members in the split etc..
import bpy
context = bpy.context
scene = context.scene

def parent(name):
    ob = scene.objects.get(name)
    if not ob:
        ob = bpy.data.objects.new(name, None)
        scene.objects.link(ob)
    return ob

def material(name):
    ma = bpy.data.materials.get(name)
    if not ma:
        # add a new material as in link
        pass
    return ma

# iterate thru all obs in scene
for ob in scene.objects[:]:
    split = ob.name.split("_")
    if len(split) != 4:
        continue
    a, b, c, name = split
    ob.parent = parent(c)
    # add materials etc.

Works wonderfully well, thanks for the prompt response. I couldn't work out what your material 'def' was doing, so I just rewrote the script slightly (added as answer to allow styling)

Working rewrite:
import bpy
context = bpy.context
scene = context.scene

def parent(name):
    ob = scene.objects.get(name)
    if not ob:
        ob = bpy.data.objects.new(name, None)
        scene.objects.link(ob)
    return ob

# iterate thru all obs in scene
for ob in scene.objects[:]:
    split = ob.name.split("_")
    if len(split) != 4:
        continue
    a, b, c, name = split
    ob.parent = parent(c)
    # add materials etc.
    mat = bpy.data.materials.get(c+"_mat")
    if mat is None:
        # create material
        mat = bpy.data.materials.new(name=c+"_mat")

    # Assign it to object
    if ob.data.materials:
        # assign to 1st material slot
        ob.data.materials[0] = mat
    else:
        # no slots
        ob.data.materials.append(mat)


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Loop cut and slide ignores a face, why?
I just want to know why loop cut and slide ignores the face in the picture and how to fix it. I have checked and found no extra vertexes and i have already tried w--remove doubles and that didn't fix the problem.
Here's the model: http://www.pasteall.org/blend/40904
And here's the picture:

Thanks in advance
I have already checked the other questions that's similar to this one and the answers didn't help.

I dont have that problem, but you have N-gons in other places that will stop the loopcuts

wow strange, what do you think it is

but it worked for you

can it have something with my mac to do

cegaton you deleted a face, when i deleted the face it worked for me too but is there a way for me to loop cut without deleting the face?

Maybe a bug in your version of blender where you have faces extruded from the surface.


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How to model a plastic food tray?
I'm new to blender and would like model a plastic food tray.
Which is the best way to model it ?

mesh cube and mesh cone, add modifier boolean operation union

Try to model only one half of the object, then enable the Mirror Modifier and check the X and Y boxes under Axis option (remember to have the origin point placed as pictured below). Apply the modifier when you're done with modeling. You may then add the Subsurf and Solidify Modifiers.

You can easily model the curved corners of a tray using the Spin tool. To make the ribs, divide the surface using Loop Cut tool (Ctrl+R). Select one face, press E and then S to scale it a bit.

Now select the next face and press Shift+R to repeat the earlier operation. Do it with all the faces.

Select all faces and extrude them (E)

You may scale them horizontally for better effect. Scale one, click the next one and use the Shift+R shortcut to speed up the process.

Use a Loop Cut tool again to make the edges of the ribs sharper.

mirroring is the last part. How did you come to the first part ? Are these surfaces ? How do I make the ribs in de side wall ?

I've updated my answer. Check it out :).

@cegaton thanks for a nice trick! Haven't heard about it before. It is never late to learn :).


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What do people buy 3D models for?
I am just wondering why people or companies purchase 3D models in the first place despite their cost.
I have been planning on making 3D models for sale and I have browsed through websites selling them like TurboSquid or CGTrader, but I start to think about how people use 3D they purchased. I mean, the collection of 3D models on these websites are huge and there are hundreds and thousands of amazing artworks, but I just can't figure out why companies buy them.
For instance, some models are shops like a Starbuck outlet, a skyscraper or industrial buildings. Why people buy them? Are they for rendering? (but what's the purpose of rendering a single building) Are they for product demonstration? (but then it is almost impossible to find the exact building that matches the companies' requirements) Are they for animating? (but a scene usually composed of quite a number of buildings and buying lots of them would be really costly)
This situation confuse me even more when I am looking at expensive, high-end, realistic models. They look stunning but why on earth will someone buy a single high quality 3D model for? (Like a futuristic lazer gun)
I hope someone can answer it specifically on the reasons to purchase 3D models, I have watched some videos regarding this issue but they just give explanations that I just cannot understand (like buying a single cat model for animating :O ) Any help is appreciated.

People buy things they either cannot create otherwise, or which provides an acceptable trade-off in cost to acquire versus time to create. I think this is exactly where the 3d model market is aimed.

I have bought a couple models before from TurboSquid. The main reason is time. I work for a medical company. When the boss comes in and needs an animation in 2 days I dont have time to waste spending 5 hours modeling some medical device when I can just buy it for $50 or so. It would cost the company more to pay me to make it than just buy it. It saves me time and the company money.

The main reason is because it's cheaper to buy the final model than it is to pay an artist to create the model. Since the model can be sold any number of times as well, the original creator benefits despite selling it for less than it cost them to make. I've used models that cost over \$200, but would otherwise take well over a week to create, and that's assuming I could find all the references needed to create the model.
As to the types of models and their uses, that depends on the situation entirely. I would imagine a lot of the models like buildings are used as backgrounds for ads or commercials, or as background models for animations. Depending on the situation as well, the models could be used as the focus of the animation, but as you mentioned that is pretty rare as finding exactly what you need can be tough.
I can (try to) lay out a hypothetical situation to make things more clear. Say a company wants a 30 second ad created involving a flyover of a city and the camera then drops to a parking lot where something happens. Assuming none of this can be filmed in the real world, there's a lot that needs to be created. Let's say that it would take a single artist 2 weeks to create the entire shot from scratch. If the artist gets paid \$200 a day (probably on the low side) and works 6 day weeks, you have a total cost of \$2,400. That's not including any textures or references that may need to be bought. Now lets say there is a 3d city scene available for \$500, plus a parking lot scene for \$200, And a fleet of cars for the lot for \$400. Some background images could be used to speed things up, adding \$50, and some sky HDRi's for \$100. We're now sitting at \$1,250, but there's probably a couple days work for the artist to add it all together and create the final elements or modify the bought ones. Say that adds another \$400. We can round the total cost to be \$1,500, or \$900 less than paying the artist to do everything. This isn't entirely accurate of course, as it's just some random numbers and times, but the point is that despite the costs of the models, which can seem high, time is money, so it's a matter of what is the cheapest.

Most times it is cheapest to pay the artist, use the artwork, and also get a license to re-sell the artwork. Most artists do not know how much to charge and sometimes this way it is possible to get an artwork that pays for itself and is free. So to all reading my comment - be confident and set prices accordingly, I sure didn't when I started out:) It's easy to get intimidated by price of online un-original assets.

That is a very good point. I guess I was thinking more along the lines of initial costs only, but I obviously overlooked something. Appreciate the advice too :)

Really inspiring. I thought hiring part time artist to make models would cost less than buying each item you want, but looking at your hypothesis it seems it is actually more sensible for companies to buy models online. Thanks.

As Jerryno correctly pointed out, it can be as you imagined as well. I do know from experience that it can be as I stated, as I've worked with $250 models that wouldv'e taken at week minimum to create not including finding references and ensuring accuracy.

I'm working on a large animation project and I'm using 3D models because they save a lot of time -- and of course I can't do anything. It's better to focus on the animation and the story development, while using excellent models that would take days or weeks for me to produce, maybe with not the same quality.


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Why some faces have different colours and can't bridge with others?
The two selected faces as shown in the screenshot have different colour (slightly brighter) and their edges was unable to bridge with others. What should I do? Any help is appreciated :)

Try removing doubles (from W menu) and recalculating normals (Ctrl+N). There seem to be  many double faces between visible ones (probably created while extruding). Also it seems in this case you may create face by F instead of Bridge tool, it's faster.


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How to know the corresponding face of an object in UV view?
Just a quick question here. I want to know the corresponding face(s) of the object I've selected in the UV view. But all faces of the object are selected so I'm unable to do that. Any help is appreciated :)


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Can I edit an armature's size through its bounding box?
Let's say I have a human model and I want to give it a certain height. Currently I only see a way using the scale (either with the mouse or by editing the numbers) but I don't even know its initial size so I can only scale it approximately.
So is there a way to see a model's bounding box dimensions and edit them to resize the skeleton?

An armature object doesn't provide it's bounding box size. However the mesh object of your character does. You can scale your mesh object until the height is to your liking (the dimensions are visible in the properties sidebar). By selecting your armature, then shift selecting your mesh, the mesh object is active and will display it's dimensions as both objects get scaled together.

If your character is made of several items you will only see the size of the active object, a trick there is to add a cube and size it to the height you want, then use it as a reference and resize your character to fit.

Thank you. Yes, my character is made of several parts. So in this case it is still basically approximate scaling but with a reference to assist. I tried to use Python to compose a total bounding box but it didn't quite work. Here's my attempt, it would be great if someone could fix it (and post it as an answer) or explain why it can't work: http://pastebin.com/Mg5Mczf5.

This is an addon I did a while back Post your script as a separate question to get feedback.


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Maintaining UV's when downsampling a mesh
I'm trying to get a high, medium and low poly version of a mesh working in my game, using the same diffuse and normal map texture. However my models don't maintain their UV coordinates when using Decimate modifier.
I'm very new to Blender but I've created an Asteroid object using Subdivision surface plus Displace modifier.
I apply these modifier once I get the shape I want and then use the sculpting tool to make a few modifications.
I have a rock texture which I set to a high X and Y repeat. It also has Coordinates set to Generated and Projection set to cube. When displaying in Rendered view it looks ok.
So I have a very high level source model with over 300,000 faces. In edit mode I select everything an do Smart UV Project. In the UV/Image editor I see the polys mapped to the texture.
I then use the Bake option to render out the high resolution diffuse map.
I duplicate the object and use the Decimate to reduce it down to 60,000 polys and Bake a normal map using the 300,000 poly version.
I then duplicate it again and create 10,000 poly and 500 poly versions.
However then I create materials that use the baked diffuse and normal maps they don't map correctly any more. It seems Decimate doesn't keep the UV's.
So how an I do this in Blender? I need to take a very high res model and create multiple levels of a mesh but use the same diffuse and normal map.
What am I doing wrong?

Sounds like a good use case for a multi resolution modifier. That said, since you are using smart UV unwrap, could you duplicate the object, apply the modifier, and re-unwrap for each detail level?

@someonewithpc Actually the decimate modifier does preserve UVs.

@gandalf3 then what's the point of the question?

@someonewithpc How should I know!? ;)

@gandalf3 I could remap each lod, but I would need separate diffuse and normal map textures for every lod which is a bit of a waste of memory.

@Martin What version of blender are you using?

@Martin if as gandalf3 said, the Decimate modifier maintains the UV, what exactly are you asking?

@someonewithpc I have a feeling it's because the UVs don't match up exactly. With less geometry with which to define UV coordinates, this imprecision is kinda unavoidable..

Oh... Yes, that makes sense :D

This is what I'm seeing. The original mesh is very detailed and has small triangles. When this unwraps it can put some polys by themselves. It can also make holes, which leaves a black area in the texture. However when decimated the UV's may still be in the correct place but the polys themselves can cross over black areas of the texture as they aren't as accurate. Not sure how to avoid this?

If you want to post the .blend file I'll go through a few methods I use to lower mesh resolution while preserving UV's and if I can find something for your particular case I'll post an answer that walks you through it.  Just please leave out the textures for this one since they won't be needed for this.  If it's too big for PastAll.org, you can load it to a DropBox account.

Thanks for the advice all. @MarcClintDion that's a very generous offer, but after a little more messing about I've found what I'm looking for. I can unwrap the initial cube and mark all the edges as seems. Then when using Decimate go into the mesh and move the edge UV's back to the very edge of the texture. This would take quite a bit of time and I now have a lot more appreciation for how complicated modelling is. I've decided to use Triplanar texturing in the game as this works really well and I can have destructible asteroids without the need to recalculate the UV mapping.


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Alpha image or model?
what is better? Using an alpha image or modeling a leaf, flower, or other plant material. I've read a few places that using a modeled leaf has a faster render time. You also get more control and can add more variety if you model it yourself. But what do you guys think? This is for photorealistic renders.

For a close-up I would certainly model and texture the leaves, however, at a distance a simple alpha texture could get just as realistic of a result with much less computing power. For example if you are taking a closeup of some foliage and then zooming/focusing on a subject, modelling the extra detail would be worth the extra effort/render time. However if you just want some realistic shrubs/trees in the background, textures are the way to go. And if it is only for a very distant scene or the background is blurred, having textures for entire sections of foliage might help even more.
Basically, unless you can see the difference, there is no need for the extra polys in your scene.

Modeled leaves render faster; with, however, higher memory usage, if the polycount goes too high.

Are you sure of that?

Yeah, pretty sure. It's the method used in "The third and the seventh". The premise is that for alpha masked leaves, a transmission ray as to be created, once the surface is hit; if you use a model, you can avoid a lot of these.

So a low-poly repeated texture mesh leaf probably is the best way. Interesting! What if you are using glossy, translucent, and other complex shaders?

I would assume the same, but I'm not sure

If you use photorealistic renders, use model, because it will make it smoother and you will get exact leave as you want. Use alpha leaves for games or quixk renders used for movies and animations;)

Especially for BGE (blender game engine) alpha textures would be the best due to limits on vertex count.
Just make sure if you're using an masked image that you didn't create, that you have the proper licensing if you go public.


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Make thick defined smoke
I want to create very thick and defined white smoke. Should I model it with displacement or use the smoke simulator? Note: this is a still image.

It's a lot easier to get realistic results with the smoke simulator, however it will take longer.
A quick (and rather terrible) attempt at mesh smoke:

To create the mesh smoke I used a subsurfed cube with a displace and a remesh modifier, which I extruded randomly and duplicated around in edit mode.
Smoke sim:

There are some tricks to getting smoke sim bake times down for a still, for example you can use a faster time scale and/or a quick moving particle system as the emitter in order to get the smoke into position in a smaller number of frames.

To get a nice thick white smoke, try using larger number of volume bounces and a lot of light. In the above images I used 5 volume bounces and a strength 5 sun lamp.
You can set the bounces in Render settings > Light paths:

Also make sure you have a pretty dense volume shader with scattering.
For a smoke sim a simple way to tweak the density is with a multiply node:

Wow! Thanks I'll give this a go and report back. Thanks!


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Is there a way to have my emission shader only affect the particle system?
I have a scene that has a particle system and other objects. The particles are an object with a pure glossy shader. I have a plane that I have setup as an emission shader to reflect off the particles. However it is washing the other object in the scene. Is there a way to have my emission shader only affect the particle system?
Thanks

What you want is light groups. Well, the light groups feature hasn't been implemented in Cycles yet. If you wanna separate lighting on different objects, including particles, using Cycles, you might use render layers. Here's a solution for a practically the same question as yours.