text:
How do you make objects appear in a blender scene at specific times?
I am creating a blender animation that involves an explosion. I created the explosion object in a separate blender file, but if I import the object into the main scene, It just plays the explosion animation at frame 1. But I want the explosion to happen at frame 245. Is there a way to make the object come into the scene at that specific frame, or can I at least keep the animation paused until then? Or am I thinking along the wrong lines entirely?
Note: I cannot just create the explosion within the main file because it gets all dragged out and it stutters. It works fine when I import it, it just happens too early.

While you can animate the visibility of an object, I think you are more interested in adjusting the timing of the animation. Using the dopesheet you can select the keyframes of your animation and move them along to start at frame 245.
Similar tot he 3dview you can use A to select all keyframes and G to move them. After grabbing the keyframes you can also type in the number of frames you want to move them.

You may also be able to render two separate animations and join them together in the VSE


text:
Black artifacts when looking through many transparent objects?
Using v2.73, cycles and a very simple scene: an array of cubes, no big deal.

If I set the shader's material to transparent, the cubes in the foreground do become transparent but those far away in the back do not disappear completely and this strange dark things appear (visible in rendered mode and in final renders)

I've played with the clipping distance on the viewport and camera, but I can't figure out how to make those ghosts go away...

crank up the transmission in light paths in render tab

it's transparency not transmission sorry, try again

Related: http://blender.stackexchange.com/q/18857/599

I panicked when I saw you asked this question and felt so relieved after scrolling down and seeing an accepted answer!

Me as well hit the panick button, good grief thanks

Related https://blender.stackexchange.com/questions/42023/transparent-textured-planes-produce-black-artifacts

Go to Light Paths under the Render Tab and turn up the Max amount of transparent bounces until you have enough for every cube.

For 2.8* set the Transmission bounces in the Render section>Light Paths>Max Bounces

you saved my day

transmission or transparency?

Although that answer has lots of upvotes, it mixes up Transparency and Transmission bounces, especially because when it says that from Blender 2.8* upwards you should increase the Transmission bounces. But that's wrong, this wouldn't help in this case. Also it doesn't give hints on the dependencies between Total and Transmission bounces. In the screenshot they both have a value of 12, which is okay. But if 12 wasn't enough, increasing only the Transmission bounces won't make a difference - whereas Transparency (which is what's needed here) would work when increased.

The reason is the Max Bounces setting for Transparent bounces under Light Paths in the Render Properties.
As it seems, you have a value of 0 there. I would rather suggest setting it to a much higher value like 64 or even 128. It doesn't increase the render time very much but you can avoid black artifacts when too many transparent objects are overlapping themselves. Also black artifacts in smoke simulations are much less likely to happen.
The problem doesn't occur in Eevee since it's not a raytracing engine and doesn't use the Light Paths settings for bounces etc. The background is still transparent since it is not "bouncing off" rays so it's not limited to that setting.
It is not necessary to increase the Total bounces, since Transparent bounces are independent from the Total amount while the other values are not. You'll find it here:

Here is an example: When you have one plane with transparency in front of another object e.g. a sphere, the object behind it will be black in the transparent areas just like in your screenshot, because the Transparent bounces are set to 0.

If you now simply increase the value to 1, the sphere will no longer be black behind the plane. But if you put a second plane in the scene, the sphere only shows correct behind the one or the other plane. Where they are overlapping it has turned black again, because there are 2 transparent layers. You can imagine that using small values will quickly give bad results for example on tree objects holding lots of leaves with transparency.

source: Stack Exchange

license: 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/

sort: votes


text:
Using the Camera Data Node
In the blender manual the options for camera data node are explained like this:

View Vector
A Camera space vector from the camera to the shading point.
View Z Depth
How far away each pixel is from the camera
View Distance
Distance from the camera to the shading point

So, what is the shading point? How is each of these options different form the other, and in which cases should one be used instead of the other?

Related: https://blender.stackexchange.com/questions/111070/how-to-emulate-camera-distance-in-cycles-node-system

Related: https://blender.stackexchange.com/questions/132827/camera-data-view-vector-interpretation

Shading Point
is the nearest point of intersection of the camera ray with a visible object, which the render engine is currently calculating the color for (these calculations are referred to as shading)

The real View Vector
it is a vector (or a ray) in the camera space, starting from the center of the camera (or the view) and reaching the shading point

View Vector
it is a normalized view vector (magnitude = 1 or unit vector) in the camera space, starting from the center of the camera (or the view) and pointing at the shading point (it doesn't necessarily reach it )

View Z Depth

it is the Z component of the view vector (the non normalized)
it is the shortest distance from the shading point to the camera's XY plane (the is not normalized Z-depth, it is not from 0 to 1)

View Distance
it is the magnitude of the non normalized view vector, or simply the distance from the shading point to the camera's center

where to use each one: well you know enough now to decide where to use them!

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

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


text:
Lamps not casting any light
(On blender render, not cycles) I turned off ambient occlusion to get a faster render for a while and I just realized my lamps don't work, Hemi, Spot, Sun, Area, Point... None of them cast any light, the scene is just completely black, I don't know what's going on! Help.

Are your lights on the same layer and are they render restricted in the outliner?

Is it possible you could upload your .blend?

There are multiple reasons why you are experiencing this , but without a picture of your scene settings or more info on the file in question is very hard to guess.

maybe he went blind :O!


text:
Snap to grid using knife tool
I have a situation where, after extruding an angled face, I need to make an edge of it flush with the grid lines. I tried to illustrate what I want to do with the image below. Note, the new location does not lie along the intersections of the grid, only along the X line, so I cannot use snap to grid.

I believe the best way to accomplish this would be with the knife tool, but I need a way to snap it to the grid in order to get accurate results. Is there such an option? Bisect would also work.
I am aware I could use a second object and intersect them to get this result, but I would prefer if a tool could accomplish what I need, as my current project will involve a lot of this.

(Edited)

Snap a 3D cursor anywhere on that X line you need.
Create a new plane.
Press R to rotate, then X to lock to X axis and rotate a plane so it would be intersecting your figure.
Go to modifiers tab and add boolen modifier.
Select your figure as an object.
Apply a modifier.

It should create a vertice on the intersection that you can use with snap tool.

That doesn't seem to work, at least in my version, as intended. It snaps to the edge, but ANY point along the edge, not just the intersection with the X-line. The vertex only moves along X... but not to the desired position, because the snapping point moves freely along the edge. Picture of the result: http://i.imgur.com/NYQcgjO.png

You are right, that way didn't work, I've edited the post. Now it works with planes but I'm not sure if it will work with complex geometry.


text:
Applying Textures in Blender
Hello I'm pretty new to Blender, and I need some help with applying premade textures to models I've downloaded from blendswap.
So If I download this model for example: http://www.blendswap.com/blends/view/78361
and import it to blender, the model added doesn't have the texture. All the models that I import look like this: https://i.stack.imgur.com/Fktfj.png
How do i go about adding the texture that the author already made?

Your viewport is using solid shading, which looks right. Does rendered preview or full render show the material? You change the viewport to rendered preview in the menu next to Object Mode

Have you tried Shift-Z? that will take you into rendered mode. Also, how did you "import" the model, if you used link or append, you may have left the material behind!

What do you mean by import? It is already a blend file, so you can only append or link data from the file into another file.
If you are appending some parts, make sure you are selecting everything you need and, in that case, that you change your render engine to cycles before rendering (it will render grey otherwise).
It should render correctly, that model doesn't have much for textures, the most noticeable is the chair color.
In the viewport, everything will look grey if you are on 'solid mode'. See more on that here: http://www.blender.org/manual/editors/3dview/shading.html

You are using the Cycles Render, so the colour does not show up in the viewport, but if you hit Shift+Z to change to Rendered View, you can see the image rendered in the view port and then you can see the colours.


text:
Scrolling the mouse wheel scrubs the timeline
Since I updated to 2.74, sometimes the mouse wheel scrubs the timeline rather than zooming. I guess I've hit some key by mistake, but I haven't been able to find out which one. When this happens, scrolling scrubs the timeline no matter which part of the UI I'm in, i.e. it won't let me scroll up and down in the panels either.
Update: I have several virtual desktops, and after posting this, when I went back to the desktop where Blender is, it had reset the mouse function to what I'm used to. Seems strange. Is this a bug that I should report, or is it some feature that I haven't been able to wrap my head around?

It could be the OS causing the problem.  Could be drivers.  Could be Blender.  Without concrete steps that can reproduce the problem, the report will be closed right away unless many people are all saying the same thing.   The best thing that you can do for yourself is to find some action or series of actions that will reset Blender's grip on user input/output so you can get back to what you are doing.  Maybe push the escape key several times, or double click the header bar, try Ctrl-S then Ctrl-O to save and reopen, etc....

@MarcClintDion I'll try to make notes of what I was doing right before it happens, and see if there's a pettern to it. I'll also consider contacting the maintainer of the FreeBSD port and the maintainer of the window manager I'm using, but I'll try gathering some more data first. Should we put this on hold for now, or should we leave it open?

For me, ever since I upgraded to Yosemite(OSX), whenever I switch between the IRC app(Colloquy)  and Blender's Node Editor, the movement of the Node Editor becomes "attached" to the OS mouse cursor.  When I move the tablet pen around, the Node Editor goes bonkers and jumps all over as if I'm left-clicking and dragging while jerking the pen around violently, even though I already released the button and hardly move the cursor.  It's really bonkers and only seems to happen between the switch from the IRC window to Node Editor.  For three years it never happened and now it happens every time. :)

I believe this one is related.

I have the same problem! On Ubuntu not using a virtual machine.

In different windows, Alt + scrolling the wheel scrubs the timeline.
Hope it's an helpful info.

If I hold Alt while scrolling the wheel nothing happens. Nothing at all. And even if it did, I don't think it'd solve my problem, because my problem is that it locks itself to scrubbing the timeline.

this doesn't work for me either.  I tried hovering over several window types to see if this made a difference.

Alt+scroll works in the compositor for me, but this still doesn't answer the question imo..


text:
Cannot duplicate selection
I am doing this Blender Guru Tutorial  How To make a Beer. At about 18:30 minutes Blender Guru is making a duplicate of a selection (that has to become the beer in the glass).
I am trying to do the same but somehow I cannot make the duplicate.
Here is my blend file. Can someone help me?

You have proportional editing on (the blue icon in the 3d view header) with a large proportional size (a large circle that appears when you try to transform) so when you try to move the duplicate mesh it moves the entire object and thus appears to have no effect, toggle it on/off with O or by going to the menu and choosing Disable.

After that to duplicate and separate, use Shift D, confirm with left click and then press P > Selection.

thanks for your reaction. When I disable Proportional Editing I still cannot make the duplicate ???

@JanScherders in the file you sent you already have the selection, see the last sentence in my answer.

I did what you say ...open file, disable Proportional Editing, Shift D ... but it does not work.  I am trying for hours now, pfff ;)

@JanScherders I understand the frustration when simple things don't work ;), join me in chat

I know I have to do Shift D and Separate Selection but somehow the duplication does not work

@JanScherders I gave you write access, you should be able to speak now.


text:
How can I make the "R" key only rotate the object around the x & y axis?
I have managed to make a change so that the the default rotate function for "R" (free) gets locked around the Z axis when in the perspective viewport. The problem is that when I do that Blender will not rotate around the correct axis when you enter the left, right, top viewports etc. Is there any way to keep Blenders' default on all viewports except the perspective one?

What if you use a different key for your customized locking rotation, and keep R as the default?

It seems like a backwards sollution, but thanks for the suggestion.

Wait a few minutes, I'll write this addon for you

On second thought, this was harder than I thought (misunderstood your question). Might do it later today tho.

Thank you that would be great! did you read what sambler wrote aswell?

When you press R to rotate the object, press either X, Y, or Z on your keyboard. That will allow you to only rotate on one axis.

Thanks for the answer but i already know that. The reason why i wanted to change this is that i don't have to press the x,y,z ever time.

Oh, okay. Sorry for misunderstanding.

Blender doesn't offer the options you want but I expect you can achieve this with an addon.
By creating your own rotation operator you can look at various properties then choose which options to set when calling the existing rotation operator. Then you replace the key-binding to run your operator instead of the standard operator.

Thanks! I am not skilled enought to code this but its great to know that it can be done!


text:
Is it possible to make seams thicker in Bender?
Is it possible to make uv seams thicker in the 3d view in Blender?

At the minute, no, that does not appear to be an option. You can view all available theme options for the 3D view by going to File> User Preferences> Themes> 3D View:

Yeah i have looked inside here before. Its wierd because you can change the width on "highlight selected" so i was hoping perhaps i had missed some settings somewhere. anyway thanks!

If this has answered your question, feel free to mark this question as 'accepted' by clicking the tick icon next to the answer. See:http://stackoverflow.com/help/someone-answers


text:
UV pie menu, need help with rip command (two functions in one)
I recently made a pie menu for the uv editor to speed things up. It's activated by clicking on the RMB. One of the command "rip faces" doesnt work the way i want to at the moment, here is what i need help with. When you select the rip faces command in the pie menu you still have to press "g" in order to move the ripped face, this is a little backwards since the whole idea with the pie menu is to not have to use the keyboard at all.
Is there any way you can have "two commands on one button"? (rip + "g")
If some on e could provide me with the code for this it would be great.
Here is a link to the script: http://blenderaddonlist.blogspot.se/2015/04/addon-jimmy-pie-uv.html


text:
Make blue glass shader in cycles
I would like to make a blue glass shader in cycles.
Something like this:

This was my first trying but I think it's terrible.

And here's my second trying but it doesn't look well.

Is there any way to make a shader like on the first image?

Try to mix two Glass Shaders- one with a white color and the other with a blueish color. Set the mix factor to a low value to make glass look more blueish and transparent at the same time. With a good lighting setup you'll achieve the effect you want.


text:
World view does not display face/vert count
I started working on something in a new scene and for some reason the total face/tri/vertex count for everything in the layer i am on is not showing. This never happened before, is there a way to fix it?

for example linked groups don't show face/tri/vertex counts.

The vertex count uses objects in visible render layers. If you are on a layer which is not visible in the scene renderlayers, then this is what happens.

This is because the info panel displays scene wide information, but the visible viewport layers can be different between multiple viewports.
Since the viewport layers are locked to the scene layers by default, this doesn't happen all the time.


text:
Blender Python mesh.from_pydata?
I want to generate a mesh with this command I found in the API:
mesh.from_pydata(verts,[],currentFace)

But this gives me an Error:
File "C:\Program Files\Blender Foundation\Blender\2.72\scripts\modules\bpy_types.py", line 409, in from_pydata
self.loops.add(sum((len(f) for f in faces)))
File "C:\Program Files\Blender Foundation\Blender\2.72\scripts\modules\bpy_types.py", line 409, in <genexpr>
self.loops.add(sum((len(f) for f in faces)))
TypeError: object of type 'int' has no len()

I don't know why my script can not make a mesh from the variables verts and currentface, which are both lists. I also printed a line before to check their type again and whether they contain elements:
print(verts,currentFace)
>>>[[40.0, -10.0, 70.0], [40.0, 11.0, 80.0], [40.0, 11.0, 35.0], [40.0, -10.0, 30.0]]
>>>[0, 1, 2, 3]

Could someone help me out? Thanks.

related: http://blender.stackexchange.com/questions/2407/how-to-create-a-mesh-programmatically-without-bmesh/

Blender includes a sample template file that uses from_pydata() which you can get in blender's text editor from Templates->Python->Addon Add Object
The key portion is -
def add_object(self, context):
    scale_x = self.scale.x
    scale_y = self.scale.y

    verts = [Vector((-1 * scale_x, 1 * scale_y, 0)),
             Vector((1 * scale_x, 1 * scale_y, 0)),
             Vector((1 * scale_x, -1 * scale_y, 0)),
             Vector((-1 * scale_x, -1 * scale_y, 0)),
            ]

    edges = []
    faces = [[0, 1, 2, 3]]

    mesh = bpy.data.meshes.new(name="New Object Mesh")
    mesh.from_pydata(verts, edges, faces)
    # useful for development when the mesh may be invalid.
    # mesh.validate(verbose=True)
    object_data_add(context, mesh, operator=self)

Of note is that the vertex list is a list of Vector() items and the face list is a list containing items that are each a list of vertex indices (eg. a list of lists), multiple faces should be entered as [[0,1,2,3],[1,2,5,6],[0,1,7,8]] - this is most likely the source of the error you see.


text:
Boolean union and solids compenetration
What is the difference between a boolean union of two solids and to left them compenetrated ? Visually I see no difference, but if I don't execute the union, internal faces remain.

The Boolean joins the two objects into a single mesh, with no inside faces, and no intersecting edges. This is important if you're trying to create a manifold mesh, or don't wan't overlapping faces. Of course when using union there is no visual difference, since the meshes are being added and the total surface remains...


text:
Material Mode in Shading Panel
I have this version of Blender

What is the difference between the two Material modes in the Shading panel ?

On my PC  GLSL   seems to work, instead Multitexture  seems doesn't work.

Here's a document that explains some differences between a GPU based shader language (GLSL, HLSL, nVidia Cg) and the fixed-function pipeline. http://http.developer.nvidia.com/CgTutorial/cg_tutorial_chapter05.html However, without you showing what you are seeing vs. what you expect to see, it's going to be difficult for anyone to guess what your issue is.


text:
Simple parquetry tiling
Is it possible to create this parquetry pattern by modelling only a single tile and using some system of array modifiers, and then applying a single material, that gives each tile a similar, but individual, pattern? And for clarity: each rectangle is one tile, and each square is made of four tiles. I've intentionally exaggerated the edges of the tiles, for visibility.

This is the setup I have at the moment.

I'm quite happy with the overall looks of it, but it gives a seamless pattern over the entire floor, and I want each tile to have an individual variation, like this.

Can you read your own node image? I cannot. I do not know how to ask the site to show the original image.  Do you know?

@atomicbezierslinger right click --> view image

@Chebhou.  Which browser?

@atomicbezierslinger I made the image a clickable link now. Clicking it should take you to a larger view of it.

@SixthOfFour.  How practical of you.  You must tell me how you made it clickable. It really is the best.

@atomicbezierslinger Click the "Edited ... ago" link and view my last edit. :)

With one material shared between all the rectangles, you can add randomized attributes, as long as each rectangle is a separate mesh object.
The trick is using the Object Info Node with the Random output as a factor in texture position as well as in a colour overlay.
Here's the modified Material node tree. All collapsed nodes are unchanged from the original material from the original question.

Here's a sample screenshot of the single material across the 48 rectangular meshes (16 groups of 3). It demonstrates the randomization of the colour overlay as well as the shift in Texture coordinates.

Randomizing Colour

The colour overlay is easier to explain. You take the Random value into the Factor of a Colour Ramp and then mix that over top of your base colour. The Random value will apply a different position value from the colour ramp to each of the mesh objects, giving you the colour variation you need. Adjust the colour ramp to make it as subtle as you want.
Randomizing Texture Position

This part is a little trickier. Essentially we want to modify the X and Y values of the Texture Coordinate. It's important to know that Adding to these values moves the textures, and Multiplying a number by these values Scales the Texture Coordinates. We don't want to scale here, we just want to randomly change the X and Y values of the coordinates.
The problem is that we can't do this with the Mapping node, so we need some math nodes.

First we take the output of the Mapping Node and split the XYZ values with a Separate XYZ node.
Then we add the Random value to the X and the Y values
Then we use the Combine XYZ node to combine the altered XY values with the unchanged Z value.
At this point we pipe the vector output into the rest of the node tree as was originally set up.

This way we are adding a random integer to the X and Y value and shifting the texture coordinates for each mesh that uses our single material.
Note: In this example I did not randomize the Glossy material, although you could certainly do that as well.
Tip: If you want to learn more about modifying texture coordinates, I would highly recommend Bartek Skorupa's video: "Manipulating Texture Coordinates Like A Boss"

Looks good. Really good. I upvoted now, and another +15 will be coming your way after I've confirmed it, unless something even better shows up. My mind was locked on using array modifier(s), and I didn't even consider making each tile a separate mesh. (And my bed is still shouting)...

You will still want to use the array modifier to create the quantity of tiles you need, but you'll have to apply it to get them all as separate objects. Without applying array, we don't get access to the Object Info Random value.

I figured it out, and here's a render preview. I've only done the coordinate randomisation, not the colour. I'll get to that. I created one tile, then a plane with four groups of four rectangular faces. Then applied an array on that plane to get the needed number of tiles. Finally DupliFaced the tile on the plane. It's perfect. Thanks.

And here's my floor. The ball is just there to try the reflections. I split the material in two. The diffuse one for the tiles, and the glossy one I mixed with a glass shader for a plane ever so slightly above the tiles. The artifact in the lower right is a reflection of the light source. Thanks again.

Also if you apply a dirt texture and map it by location, you can have a more variation for each tile, but also have a something that ties them together as well.

Particle System Particle Info Node
Provides [Index] value for your Convenience and Creativity

Particles.  Particle System. Particle Info. Since the particle info node will give you [index], you can base texture coordinates parameterized/uniquely to the tile. This includes 90 degree rotation. Particle System Settings depicted below.  The [index] can be used with math nodes including random numbers. Gain and Bias.
With a Particle System you need only two planes. The Particle System itself and The repeated object particle.
Particle system result with two textures, selective rotation, color progression, texture repeat.

Animation Ready

Progressive Rotation via [Index]
90 Degree Rotation along Green to Blue Diagonal

Particle Info Node Close Up

Particle system result

First Object Particle focus.
Image Below.

Particle System Full View

Illustrating Color Progression based on Particle Info Index.  This correlates with the color ramp node depicted in due time.
Image Below

Particle System Close Up

Illustrating Alternating Texture XY Coordinates.
Image Below

All the convenience of a Blender Particle System

Emitting all particles at the start of scene with a long lifetime will give the static quality.

Condensed Noodle Soup

Look No Groups
What a Mess!
Please never arrange your noodles like this

When you grow tired of that technical floor,  Add 2 more math nodes and a new texture to get something like this.

This is easy because the particle system will produce a predictable value in the particle info index.

Ordinary technique.  You can introduce non continuity by taking 3 * 3 = 9 squares of the wood texture. 6 * 6 = 36.  So some viewers might not notice the repeat.  Level of Detail.

I'll look into it to morrow... Or rather later today for me. It's 4 in the AM here, and my bed has been shouting at me for hours.

Careful .... Blender can be certainly be louder.

Also a good one. But how can I rotate every other group of four (or any number) tiles by 90°? Look at the reference image and the two renders I posted in comments to @ToddMcIntosh's answer.

@SixthOfFour . Please see above image with rotation and 2 textures.  Use a second texture, composition, or math nodes to rotate. My goal was to provide a starting point for many different people. You have a very fitted solution with 48 meshes. I have been meaning to do this for a while so you gave me a nudge. Thanks. I have take artistic or technical license. Composition of particle systems is something I might explore.

@SixthOfFour. Please place your solution images in your original question so others can see, if that pleases you.

Sorry for the delay in replying. I've been somewhat preoccupied with earning my living (Blender is just a hobby). I think editing my question to include the results of an answer is a little too close to posting my own answer. I may, at a later time, post my own answer, if I do some tweaking that I feel would be usable in a wider context, and in that case I will include images in that answer.

Using OSL you can do this with one script node, this script was originally a renderman shader. The drawback with OSL is no GPU support.

Script can be downloaded here.
And the settings used in the sample -

I've downloaded it and just did a quick try. Really good. But for now I'm going with the already accepted answer. The main reason being that I've already implemented it, and imported the floor into the flat I'm working on. I'll definitely save for possible future use. Thanks.

This is a handy solution, however there are some caveats. OSL scripts often take longer to render then simple mesh solutions. Also, with a texture only solution you don't have some of the advantages of the geometry edges between the tiles. If your tiles are very shallow this may not be a problem.

authors: Игорь Викторович

authors: Михаил Саприн


text:
Wringing a torus around the circumference of its major radius
Would it be possible to wring the tube of a torus around the circumference of its major radius, like this?

This was done by shifting the texture coordinates by using a Texture mapping node. However, the object I have in mind would be low poly and flat shaded, i.e. the location of the edges would be visible, so texture shifting would make the texture slide over the torus rather than giving the appearance of the tube being wrung.

Correct me if I'm wrong, but isn't that actually the minor radius?

As far as I see it, the tube rotates around the circumference of the major radius.

@gandalf3 Thanks for pointing it out though. I hope my edit made it clearer. To be specific, what happens here is that any circular cross section of the tube rotates around the normal to its plane.

you can use a cylinder with array and curve modifier :

apply the array modifier and Unwrap the cylinder then you can get the result :

Thanks. I got it :) (Though I need to get the length of the cylinder better fitted to the length of the curve).

@SixthOfFour the length was a problem I didn't use fit_curve it was leaving some gap i had to proximate it, just resize the curve slowly

It's just a little math. I used a bezier circle with default settings. If I use a circle with the same number of sections as the cylinder, it'll be easier.


text:
How do the solid OpenGL lights found in the system preferences work?
Where can I find a detailed explanation of this topic ?
For example, where the lights are located, which type of lights they are, which is the illumination model, etc.

You could start with this - "The first is the key light on the left, and the second is a dimmer full light from the right.A third light is also available, which by default is set to provide highlights from the lower right." From book  "Mastring Blender" by Tony Mallen, https://goo.gl/cI2DfJ.

All three are directional lights with the direction relative to the view angle (think sun lamps parented to the camera). The direction is controlled via the direction widget:

There are no differences between the three AFAIK, three was just the number chosen to be hardcoded in.
They will add to each other when their areas of illumination overlap.

What are AFAIK ?

@Valerio AFAIK = As far as I know


text:
selecting many objects inside blender and export them as seperate .obj with one click?
I am currently working on a huge scene with modular building blocks and for the moment I have to export one object at the time which is extremely time consuming. Is it any way to select say 30 objects inside Blender and use the .obj exporter/some kind of script to export each object separate instead?

related http://blender.stackexchange.com/questions/5382/export-multiple-objects-to-obj?rq=1 (but that asks about all objects in the scene, not the selected only)

I've written an Add-on, see http://blender.stackexchange.com/a/31852/3710, as usual you only have to enable selection only.

certainly! but it's a little hacky.  Run this from text editor for a few objects selected. Make sure to change the folder to a valid path.
import bpy
import os

folder = '/home/zeffii/Uploads/'

selected = bpy.context.selected_objects.copy()
bpy.ops.object.select_all(action='DESELECT')

for obj in selected:
    name = obj.name.replace('.', '_')
    obj.select = True
    fullpath = os.path.join(folder, name + '.obj')
    bpy.ops.export_scene.obj(
        filepath=fullpath,
        check_existing=True,
        axis_forward='-Z',
        axis_up='Y',
        use_selection=True,
        use_animation=False,
        use_mesh_modifiers=True,
        use_edges=True,
        use_smooth_groups=False,
        use_smooth_groups_bitflags=False,
        use_normals=True,
        use_uvs=True,
        use_materials=True,
        use_triangles=False,
        use_nurbs=False,
        use_vertex_groups=False,
        use_blen_objects=True,
        group_by_object=False,
        group_by_material=False,
        keep_vertex_order=False,
        global_scale=1,
        path_mode='AUTO')
    obj.select = False

Most of those options in export_scene are default and you can remove those lines, or comment them out, but some of them may be useful if you want to change them later.
There's a nice Template for this in (with a slightly different approach - as in, it checks to see if the destination is valid first, which is handy if you aren't too familiar with paths):
TextEditor -> Templates -> Python -> Batch Export

update:
https://gist.github.com/zeffii/529d435d5853e92dcc51
I'm not entirely sure how to inherit all the properties from the original exporter operator for objs. I could add them individually if you need specific props, else it would be wasted effort adding them all.
With the exporter code, you navigate to select a folder, don't have to type any thing, just hit the Export selected Objects as obj button at the end.

Big thanks! I will try it out and i will mark this solved if it worked.

Thanks but it didnt work, also i dont understand what the template is suppose to do, should i run that to check the validity of the filepath i write in some text inside the text editor? can you help me to write a script so that i can attach it to a shortcut instead? thanks!

Yeah, I almost finished the add-on code for it, which would let you pick a folder from a panel instead.

but in the meantime, you sould start blender from a console / prompt and try running the code, in order to get the error. ' it's not working ' is too vague

I've added a version of the script which when Run, in TextEditor will add a menu item to File -> Export. see the update

Thanks a ton for helping me with this! I really have no clue how to script and this will help me a lot in terms of time. I still havent tried the script, i will try it and if i get any errors i will paste it here as well. THANKS!

Okay i cant get it to work am i doing something wrong here? here you can see the screenshot: https://www.dropbox.com/s/vp8k4hgn3d7aab2/error.jpg?dl=0

Let us continue this discussion in chat.

Funny, same idea :) Here you can find this as File Browser Add-on (user selection also implemented): http://blender.stackexchange.com/a/31852/3710. Feel free to improve it.


text:
How do I get bevelled edges from the inside of a mouth?
EDIT: Unsure how I solved it. Someone commented the corrected file, but idk how they did it.
I'm currently creating a face rig, and I'm at the modeling point of the process. I have all of the modeling finished except for one part that I want, but do not know how to do.
Here's what the face looks like (for reference):

As you can see, everything is looking quite smooth. What I want to do is have the corners of the mouth beveled so that it isn't a rectangle mouth, but a roundish rectangle. What I want is red, what I have is black:

In edit mode I discovered that the edges of the mouth are glitched out. When I try to subdivide the faces, it isn't divided into fourths, but vertices are added at the edges instead, which is not what I want.
I know that I need bevels or subdivisions to do this, but the faces are just too glitchy. Can someone give me an alternative approach? If you can teach me how to do it with mean crease, here's a picture of what edit mode looks like:

Mouth edge, same on other side
Thanks for reading, I hope you can help! :]
EDIT: Here's what I was looking for. It's solved:

[UPDATE] Here's the file: http://www.pasteall.org/blend/36339

I think you may start with this - http://i.imgur.com/TEi18ZP.jpg. (blend file is this - http://www.pasteall.org/blend/36343). I also think there are a lot of problems with that model, particularly with topology. You couldn't achieve roundish edges on the original file imo. You might want search for "good topology" in google (like this lesson - https://cgcookie.com/blender/lessons/topology-overview-human-head), because I changed only mouth, while everything else was left unchanged, but it should be. Good luck!

@MrZak Part of the problem is the model I had to begin with at first. The head never started off as a square; It was a premodeled head from a video game, which was completely rounded. It's glitchy because to make the face rig I had to flatten out the part the face is on.

@MrSquer please don't edit the title as SOLVED. Write an answer instead.

@MrZak can you please write an answer detailing the steps that you took to correct the file? The idea is that others facing a similar problem can learn and not have to rely on you fix it for them.

@cegaton Whether it is really correct fix to make it as public solution? Also, I didn't understand whose fix used OP when saying that the problem is solved and who was that "someone" who "commented the corrected file".

Looks cool @MrSquer. Do us a favour and in true Stack Exchange style write a small answer to your own question, so you can accept it. Else no-one will ever know what happened here if they find themselves in a similar sitation they mind want to try the same. This is the "Exchange" part of what we do here.

@zeffii I have no idea what Mr Zak did.

@MrSquer you could say that my solution was good enough for you, then there wouldn't be no unclarity. I absolutely didn't know about that and that's why I wasn't going to write further description.

The original file is this:

First, I removed 129 doubling vertices (W -> Remove Doubles).
After some basic tweaking (dissolving some edges and adding 2 loopcuts to make vertices adjacent) got this

Now, mouth and teeth form. I decided to drop original vertices of teeth and combine them with loops of mouth and of the hole head. To do that, I deleted top teeth vertices (X -> Faces), selected one vertice from base of the top teeth and one from base of the bottom teeth and pressed J to make edge.

I did that for all adjacent vertices forming base of teeth.
Then, I added loopcut (Ctrl + R) across the all head. I combined it with the top mouth edge so it to let me add more loopcuts without creating NGons:

Then I added 2 loopcuts across the head including mouth. I scaled them to 0 by Z axis (S -> Z -> 0) and moved slightly by Z to make teeth slightly smaller. Then I began recreating teeth by simply selecting adjacent vertices and pressing F:

After bottom teeth were done, I added adjacent quantity of vertical loopcuts (in this case 6) across the mouth to let it have roundish edges. Finally, I added Subsurf modifirer and set subdivision level to 2.

There are a lot of problems left, the eyes and whole top part of face should be rebuilt also or the eyes would not be seen as they should be. Also, my approach creates a lot of additional geometry - I tend to not creating NGons so Subsurf working as good as possible.
This is what I did. At the same time, I'm not sure what did OP to make his final image.


text:
Controlling the direction of curve extrusion
Is there an easy way to control how the extruded width of a curve object is oriented, for example like this

or this

The curve in the images above has only two control points, and I got the effect by rotating one of the points. However, for a curve with lots of control points it would be somewhat difficult or at least tedious to achieve this. Is there a simpler way?

Consider changing the Tilt, In Edit Mode of the curve, N for properties, you will see a tilt angle which you can change:

Consider a lattice modifier.  Animate the strength of the modifier if that suits you

Consider a simple deform modifier

Yes, this is called Tilt. You can control the tilt of a given segment with ⎈ CtrlT:

Thanks. I think both answers are equally good, and I chose the other one simply because you already have enough rep... ;-)


text:
Can honey bee colony simulation be done in Blender?
I am fairly new to blender and I want to simulate an environment of bees flying in and out of a bee hive, collecting nectar from flowers which are randomly placed in the environment and go back to the hive. In the hive, a few bees should be simply flying around.
Can this be done in blender? Should I use additional modules?

Blender can do almost Anything. Its limitations only lie within your skill and imagination, Blender's full potential can only be unlocked when you escape the realm of reason, and go nuts.

I expect you can do a good job of that in blender, within the particle physics settings you can find some boids options, these can be used to simulate a flock of birds so it should do bees just as well. I would have some empties moving from place to place that a swarm would follow to specify the timing of the bees moving.
You can use multiple particle systems so you may want one for the bees hanging around the hive; one (or more) for each group(s) that goes off to the flowers; and one (or more) for each group(s) that returns to the hive.
You can also use particles to place the flowers around the scene.


text:
Mesh array on curve
I'm making a short animation and I would like to fit an array on a curve. But the array isn't as long as the curve.
Here is a picture.

Oh, I now see that you did everything I said to do in my answer. Try applying the scale on both objects.

I applied the scale on both of them. It worked.

There's a fit curve option in the array modifier.

When you use this, how ever long the curve is, the array amount will always change to match it. Make sure you apply the scale of both object, or it won't work.

You could try to match the origins:

Select the curve. Enter 'Edit Mode', by Tab
Select the starting vertex (where the arrows point in the direction of the curve)
ShiftS, 'Cursor to Selected'
Exit 'Edit Mode', by Tab
(While curve selected), CtrlAltShiftC, 'Origin to 3D Cursor'
Select the array, CtrlAltShiftC, 'Origin to 3D Cursor'
(While array selected) press Tab to enter 'Edit Mode', press ShiftS, press A (once or twice to select everything), 'Selection to Cursor (offset) and exit 'Edit Mode', by Tab

You could try to play with the 'Deformation Axis' in the Curve modifier as well

I think the problem is your Array modifier is operating on the Z axis and your Curve modifier is set to deform on the X axis. Can you change your Array modifier to operate on the X axis instead. This is assuming all object rotations have been applied.


text:
How do I Texture paint with Realistic Textures?
I've been working on something in Cycles Render. Basically, I'm trying to create a wolf character, and I've successfully modeled, rigged it, placed the seams and unwrapped everything correctly. But now I feel a bit lost.
I loaded the UVs on to Photoshop and placed my own created fur texture on the UVs and then loaded it into blender, but it doesn't look all that right, and the seams seem quite visible.
Then I read online that I should try with Texture Painting, but I only seem to paint flat colors on it. I can't use my own fur texture as the "paint".
What can I do?

If you don't want to paint with a solid colour in texture painting you can choose a texture to use as a brush to paint onto your object.
The first step is to define the texture, while any built-in textures can be used an image would be the most common source. In the texture panel create a new brush texture and select the image (this will look a little different if your using Blender Internal)

In the Tools sidebar T you will find a panel for Texture, choose the texture you have setup and select stencil for the mapping type. You will also see options to alter the rotation and scale for the texture. You can also create a new brush texture by clicking the + under the texture preview.

When you move the cursor over the 3dview you will now see the texture in a transparent overlay. You can use  RMB to drag the image into place, ⎈ Ctrl RMB to rotate and ⇧ Shift RMB to scale, when you  LMB on the texture it will paint it onto the image in the selected material slot. This allows you to easily place the brush texture to match up with existing texture on your model.


text:
Blender Rigify strange issue with weighting
I have a weird issue with Blender and Rigify.
I've followed this guide to create bones using Rigify and then apply automatic weighting http://cgi.tutsplus.com/tutorials/create-an-animation-walk-cycle-in-blender-using-rigify--cg-17812
It all seems to go great until I apply the automatic weighting and then I get the strangest result as the mesh seems to mostly disappear. I can replicate this each time I perform the whole process.
Any ideas or feedback? I'm stumped.

Would be easier if you share your blend file for someone to look at. One option is to upload it to pasteall.org and add the link here.

This is a common problem. Up in the top right you will see that it says Auto-run disabled. You have to press the button beside it that says reload trusted, and it should resolve your issue.


text:
Print model for craft object?
How do I unfold a model in a way that its print ready for paper crafting? Ive tried 123D Make for crafts and its not working out the way I want it too, also I dont have windows for Pepakura (?)

Hi Emily, welcome to GD:SE, your question is a little unclear. You want to unfold an already put together model to see the template for printing? Your question is also low quality to maybe off topic (we no longer accept questions that deal with 3D programs) for our site. Please see How do I ask a good question?.

You can get the desired result using the UV mapping feature.
Start with U to bring up the unwrap menu. There will be several options. Try smart UV project. After doing that, hit F6, and set the Island Margin to 0.03, so you can see the gaps. Next open up the UV image editor, and you should see the layout inside. This is how the paper template will look. If you don't like it (probably to many separate parts) you can use a manual process.
To manually define the cuts, hit Tab  to enter edit mode. Select the edges where you will wan't gaps. Be sure to select enough that it can sit flat. Hit Ctrl-E>Mark seems then use U>Unwrap and set the Island margin to 0.03.
Finally, when you're satisfied with your layout, Go to UVs>Export Uv Layout and save the image.
Useful further reading and help:

Importing an OBJ file: https://youtu.be/5t2Ntn6JDAY?t=1m53s


text:
make "z" toggle between textured mode and wireframe?
Is it possible to make the keyboard button toggle between wireframe and textured
instead of wireframe and solid?

It sure is. Just go to Blender's preferences in the Input tab. Search by key-binding: "z". In the 3D View section you will find three "Context Toggle Values" shortcuts, one being assigned to the z key only (no modifier keys). Expand this and change the value of "SOLID" to "TEXTURED".

There is a small yet notable inconsistency in labeling that, in the UI it is listed as "Texture" yet its value name is "TEXTURED" with a D on the end.

First, note that one can already activate "Textured" mode by pressing the key combination ALTZ, and change this back to wireframe by pressing the Z key. SHFTZ activates "rendered" mode, and it, too, is canceled by pressing the Z key.
But to answer the question, yes. The key bindings can be reassigned by changing the bindings in:
User Preferences > Input > 3D View > Context toggle values.


text:
How can I find help learning Blender?
I was wondering if there would be anyone willing to tutor or teach me to start with blender, and get a decent way into it...I find the wiki and video tutorials somewhat difficult because I'm not very good at self-study. I understand it might not be worth it, as there is no way for me to pay you, but maybe we could work on projects together once we finished or as we go along? I'm also very willing to help you with your projects as I learn new concepts.
Thanks in advance, I appreciate it!

Unfortunately, this is not the correct site for this; here you can only ask particular questions about things that you are having trouble with. Try to ask this is blenderartists.org

I can be interested in giving advices and get some collaboration. Please write me an email at joshsanfelici@gmail.com, explaining what do you know of blender, modelling, animating, drawing skills and main interests in computer graphics and visual art in general.

While not exactly the type of tutor you are asking about, the Resources for Blender page, under the first category, Learning, there is a link to an answer which points to two on-line courses, one geared towards high school, and one geared towards college level learners. My suggestions is to work through either—or both— of these is as a start. You need not be a student of the sponsoring institutions to use the courses, and they are free. They are also complete courses as you might find in contemporary US high schools and colleges, where some classes are conducted on line. Having worked through these, you may find you don't have as much need for a tutor.


text:
Straighten Vertices Along a Line
On a line, I need to line up the bottom vertex points in relation to a top reference vertex point. How could I reset the X Y and Z coordinates of these vertex points to essentially line them up all through use of the vector of the reference point vertex.
I do not have access to Mesh -> Transform -> Scale on Axis for aligning vertices along a line.

related http://blender.stackexchange.com/questions/28063/straighten-edges-not-on-axis

Related: http://blender.stackexchange.com/q/140/599

You could select one vertex, ShiftS, 'cursor to selected', then . (to transform with respect to 3d cursor), select all vertices, S to scale, then X,Y or Z and then 0

Align to a custom Transform Orientation
1. In Vertex Select Mode, draw an edge
You can use Ctrl+LeftClick to create and then extrude vertices.
Then with the entire edge selected, snap the Cursor to Selection using ShiftS

2. Create a custom Transform Orientation from the edge
With the edge still selected, click the "+" button in the Properties Shelf under the Transform Orientations panel.

3. Select it for use
Click the Transform Orientation button which is by default set to "Global" and choose "Edge".

4. Scale along it
You can now hide (H) or delete (X) your guide edge.
Select the vertices you want to align.
Set your Pivot Point to "3D Cursor".
Scale (S) and constrain to your custom Transform Orientation by double-tapping an axis key (XX, YY, or ZZ). Then type "0".

@brasshat This may be of interest to you. I had originally authored this as part of an answer to another question, but that question has since been marked as a duplicate and I think this answer actually more specifically addresses this question.

This is the answer that really helped me and i've used.

@kimholder Glad you found it helpful!

One way to align vertices is to use the scale tool. First, with the properties shelf of the 3D viewport open, select the vertex you wish to align to, and copy the value of the parameter you wish to align to from the appropriate information button in "transform" pane at the top of the properties shelf. In the illustration below, I will be aligning the vertices along the y axis with the selected vertex. The value I will copy is in the green box.

Now, select all of the other vertices you want to align, and scale them to the value "0" on the axis you want to align them to. This will line all of the vertices up in a single axis perpendicular to the desired axis.

Then, with all of the vertices you wish to align still selected, in the transform panel, insert the value you copied from the vertex you wish to align to into information bar for the desired parameter (the one enclosed in the green box in the first illustration. If you want to align the vertices to two axes, repeat the process for the second axis.
This technique does not work quite so well if the vertices are to be aligned to an edge which does not parallel one of the x, y, or z axes. In that case, the quickest way I know to do it is, if necessary, to define the edge to which I want to align the vertices by defining the other end, and creating the edge, then looking from a view perpendicular to that edge, to align the vertices manually moving them with the G key until they line up the way I want them. When there have been a great number of points to align, I have also sometimes had success creating a plane through the two vertices, turning on snapping, and snapping the vertices to the plane, but in my projects, this usually takes too long to set up, and it's faster to do it manually.

Another way of doing it. It may be similar to some of the other answers, but I found them difficult to follow, so here is a step-by-step guide.
Select the line of vertices. If all vertices are connected, hold Ctrl and select the first and the last vertex. If not connected, use Shift to add multiple vertices.

Press S, then X, then 0, and drag the mouse until the vertices stop changing

Do the same for the Y-axis (S, X, 0, and drag until no more change).

Then align to the desired vertex by LMB click and hold on the green arrow, dragging to the desired vertex, and releasing when the snap symbol appears

Do the same for the red arrow

The simplest one and my favorite way.

I think this only works if the axis you want to align the vertices to, is equal to the global/local/view axis. Would this work to align the vertices to an arbritrary vector(x1,y1,z1, x2, y2, z2) of 2 points ?

You could use a plane and Apply Boolean to remove the excess lengths.. The boolean modifier applies things like NOT OR AND etc so you can isolate certain parts out and draw an plane aligned set of vertices on your shape using a plane.

A regular sphere with a lot of verts.

The knife plane of awesome! (just a plane, nothing to see here)

Note that this is in Modifiers for the sphere

Make sure to get the settings right as you need!

The resulting not so sphere anymore.

Apply the modifier and its chopped and aligned!
Just like cutting an onion just .. well no tears involved.
Keep experimenting and Have fun!

Please edit your answer, as it seems you're taking images from another answer/post or tutorial. I suggest you link the image to the proper site. A cleanup of this answer is necessary.

Please do not put text like that in images.


text:
How does one hide selected faces in 3d View while in UV editor?
Is it possible to make blender hide all the selected faces on the 3D model when you are in the UV edit mode? Or perhaps create a script that does? It's hard to see what you select in the UV editor and not having the "keep mesh in sync" option activated. What I can do so far is to hide the faces by unchecking the option in the 3D view toolbar but you still get the edges highlighted which makes the seams hard to see. What I is for the model to appear as it would look in edit mode with solid shading and nothing selected, that is with standard black edges and seams visible. How can this be achieved?

It's a bit unclear to me what you mean by "UV edit mode". Are you asking about the UV editor screen layout, with the UV editor window on the left, and the 3D window on the right, or are you referring to just the UV editor window iteslf? Also, what type of 3D model are you referring to? I think the questions should have at least a screenshot, and perhaps a copy of the blend file posted to blend-exchange or a similar hosting site, with the link posted here,

But what's the problem in having option  UV and Edit mode mesh selection sync checked ?

Mr Zak, The problem is that in the "keep in sync mode" Blender moves several vertc if you move one,island select mode does not work etc. Blender has two modes for something that only needs one mode. I only work with sync off all the time so its very frustrating to have to switch modes constantly to be able to just see what is selected.

I think that is not currently possible. I'm not completely understanding what you are proposing, but there seems to be some good points.  Till now, the only option is " UV and Edit mode mesh selection sync". (you can "fake" island selection with ctrl+L)


text:
Mirrored mesh deforms unexpectedly and becomes uneven when rendered
I've got a low poly character on Blender. I modelled it, unwrapped it and textured it with a Mirror modifier on, so that modelling and texturing was symmetrical.
However, when I render it, a some of the vertices just... move, without percievable cause. This deforms the mesh, interrupts symmetry and noticeably displaces the texture, albeit only slightly. It is most noticeable in the face, whereby the eyeball on one side of the face begins to clip through the eyelid, whereas the other remains fine.
The issue is only observable when the mesh is rendered; it otherwise appears fine. When I switch between any regular viewport and a rendered viewport, I can see these particular vertices move away from their original, mirrored positions.
At first inspection, no part of the model is influenced by errant keyframes.
Any assistance greatly appreciated.
EDIT: I'm not sure how to upload a .blend just yet; I am working on it.
Here are some before and after shots that hopefully demonstrate what I mean a little better.
EDIT 2: Here is a copy of the .blend file for your perusal. This iteration does not include the texture. The issue is observable when switching between rendered and non-rendered views of the mesh.
ALee - Zombo Man
The before screenshot: Note the eye and general facial symmetry.

After I hit render: The eye on our right has begun to clip through the eyelid. The area of the texture representing the jowls/dental sphere has also changed. I have deduced that the cheekbone/zygomatic arch has changed due to aforementioned vertex movement. The texture around the neck is also seeing deformation due to vertex movement.

Some screenshots would greatly impove your question, probably along with example .blend file with simplified copy of problem parts. It's unclear now whether you have invisible but renderable copy of mesh or double vertices or something else in the scene

You can see this question for more info about adding .blend files. It seems in your case you wouldn't want to pack textures into your file, but here is link just for convenience

Mr Zak - I have included the .blend under EDIT 2; thank you in advance for your response and assistance. It is greatly appreciated.

I'm not sure about this answer, but to me it looks like a calculation approximation problem: if you add a subsurf modifier to the body mesh, even with only 1 step of subsurf, everithing goes allright (then you can apply it, to get a pure mesh). Blender is not intended as CAD and your mesh is very low poly, maybe also adding some loopcuts would resolve your odd behaviour.
Consider that, generally, we use a circle of vertex for shaping the "hole" of eyes.
Hope it's useful.

Your suggestion regarding the subsurf modifier was exactly what I was looking for; you have my most sincere gratitude! The issue has been fixed.
Many thanks!


text:
Add checker board texture to a plane
I am working with blender and I am trying to add a checker board texture to a plane that is on the back ground. this is how I was able to get it:

I am not able to make it into a solid texture, that doesnt look like this but an actual checker board.
this is my workstation in blender:

Can you share your file or just a copy of the object with the checker texture, you could upload to pateall.org and paste the link here. It looks like you are mixing two checkers together, maybe with an odd vector input, the key data is hidden inside the collapsed part that says Checker Texture.

Looks to me like you have it set as the world background. It'll likely work better (with more control) if you create a mesh plane in the background set the checkers as a texture there.


text:
Blender reverses X-axis when exporting Z-forward
When I export object as it is - in Right handed system, everything exports fine. When I try to export to use object in Left handed system, I set Z-forward when exporting and now interesting things happen. It flips Z axis as would every sane person expect, however it also flips X-axis.

Which exporter? You may find that it isn't 'flipping' - it is rotating, to change the Z-axis it may also change X by using Y as the centre of rotation.

You cannot export to left-handed system in Blender (not with default 'orientation toolkit' used by most exporters at least). As @sambler said, this only performs rotations (and uniform scaling).
Note that switching something as complex as a Blender scene from right to left handed coordinates is a nice little nightmare (think about animations, parenting, etc.), afaik nobody ever seriously worked on this topic so far.


text:
Blender - Fill Up Bezier Curves
I'm having a big problem with the bezier curves in Blender.
Im trying to fill up the curves, but i can't.
I have already saw some videos from youtube, telling that I have to clic on the 2D button.

But when i clic on the 2D button, this is what it happens.

I will really appreciate any help.
Thank you very much.

Suggest moving this to blender.stackexchange

Is that the Java logo?

exact duplicate. or deja vue

Rotate the curve till is coplanar with global X-Y plane.
Than apply Rotation by pressing Ctrl+A.
Now you can set the curve to 2D.


text:
Best way to clean Blender?
Blender recently started to act really weird, one of the most frustrating things is that Blender History states stopped working. I am looking for some advice on how to clean things that might be messing up my Blender.
Also I would really appreciate some help on how to make it as easy as possible to reinstall a new version of blender and transfer my old settings. I am using Blender 2.75a the official version today. I know that I can transfer the old settings after I install a new version of Blender but I am not sure if that's really good if some old script/settings are messing up some things how can I find where the problem is?

Here are some things to try :

first make a copy of your the config file.
restore default settings.
disable the user addons ( the ones you installed ).
enable the console and read the log for any warnings or errors ( addons could cause that ).
install fresh copy and don't transfer the settings ( in case the problem is not from your settings ) .


text:
How to check if an object is deleted?
For what I understood, I know that an object can be deleted by running bpy.ops.object.delete() when that object is active.
But how can I verify that the object is deleted?
For example:
o = bpy.context.active_object # object I want to delete
print(is_deleted(o)) # False
bpy.ops.object.delete()
print(is_deleted(o)) # True

What should I write in the function is_deleted?

I would do it by object name
def is_deleted(o):
    return not (o.name in bpy.data.objects)

# or instead of a function,
# obj will be None if the object isn't found,
# else it returns the obj reference
obj = bpy.data.objects.get(o.name)

Did you mean o.name not in bpy.data.objects?

And what if the object is deleted and a new one with the same name is created before I perform the verification, would that be a problem?

The delete operator is probably safer than removing objects via RNA methods. I don't know if it clears all references, but at least it won't fail if there are any users and I haven't seen any follow-up crashes unlike with RNA (which usually happens if users are cleared without clearing references). Other than that, I would do bpy.data.objects["name"] and catch a possible AttributeError, or use .objects.get("name") for performance reasons. BTW: it's impossible that a deletion occurs while your script is running, unless your script itself does that, because scripts run synchronous/blocking.

Did you test this thoroughly? Because Blender will not crash before it actually tries to dereference an invalid reference (dangling pointer). As far as I understand, you would need to scan through each and every datablock and check if there's a reference to the object you wanna delete and clear it (set to None), then user count should drop to zero and the object can be safely deleted.

I favour a succinct answer and have removed the extra noise.


text:
100's of Vertices all with different Y Coordinates need to be moved to same Y coordinate plane
All these vertices have different Y coordinates yet when I select them all, I cannot move all of them to the same plane of a Y coordinate. How can I move all of them without tedious work?

This may be related - https://blender.stackexchange.com/questions/35193/move-align-one-vertex-on-a-non-planar-face-to-make-it-planar. In short - scale them all by Z to 3D cursor location, which should be placed on your plane

To scale all vertices to conform to a certain "plane" in a direction (Y axis), select all the vertices you want to move.
Place the 3D cursor anywhere along the Y plane you want (IE place the cursor's Y position to the position you want your vertices to move to and ignore its Z and X position).
Change the pivot point to 3D cursor

Press s to enable scale mode, then press y to restrict scaling in the Y axis. Scale "down" to as close to 0 as possible, or type 0. All the vertices will snap to the cursor's Y position while maintaining their original X and Z coordinates.

Select all your veritces and scale to zero SY0


text:
suddenly right click selection does not work
suddenly i cannot select anymore with right click (or example objects in object mode or faces in edit mode). I was doing this tutorial and they asked me to change a few things in user preferences and now i cannot select anything.

go back to the user preferences, go to input and change select with: to right

select is set to right click. but still i cannot select anything

maybe you should look in the outliner and look at the arrows (next to the eye) of a mesh. If this is off you have to click on them so you can select the objects

what is the outliner ?

@Jan Scherders this is the outliner: http://online.ts2009.com/mediaWiki/images/a/a2/Blender_Simple_Animation_Tute-Outliner_window.jpg

i have just opened a new file. still the same. probably i am doing something  very stupid thing wrong

for you information: I am in blender 2.75

maybe you should load the factory settings

go to file --> load factory settings

i did that and still the same

hmm, maybe a new mouse?

I did restore my mac system with an earlier version ...could that be the explanation ?

yes, but i don't authorisation. my reputation is not high enough

problem is solved. I restored my mac system and now i find that the system preferences of my mouse are suddenly the standard preferences. that is why right click suddenly does not work anymore. I made the association because gladys asked wether i had a new mouse

Eventually you may try to Load Factory Settings. It'll restore your RMB click functionality, but also change all your current settings. Make sure to save your work first though.

My RMB on a mac stopped working for selecting, too.
Changing from ortho to perspective view (View:Persp/Ortho) and back again seems to fix the problem.
Loading factory settings didn't help. I could select from the outliner, but not with a RMB click on objects. It would work on a new document, but not my saved document though. This happened several times. Anyone else experience this issue?

Ask a new question please, if you think this one is related then include a link to this one as well. Answer box is only for answers to the question, not new question.

Hit similar issue and since this page is first on Google - leaving answer.
Problem:
- MacOs
- Blender 2.79
- Right button works in outliner, but NOT 3D view
Solution:
- change camera near clip distance to some low value and then back
Suddenly right click started to work as usual


text:
Modeling a wine glass with spin tool
I am trying to model a wine glass with the spin tool. But the result looks more like a cup/beaker than a wine glass.
It is my understanding that the spin tool uses the 3D cursor as the pivot point. Not sure what I do wrong. The blender file is here

Related answer: http://blender.stackexchange.com/questions/24496/how-can-i-create-a-profile-and-rotate-it-to-create-a-mesh-using-blender-2-72

Drinking glasses rarely have an even thickness, therefor you model the profile and thickness and spin it around. There exist comprehensive answers related to this process, it's not a bad question.. but it has been answered before.

You could also click on the vertex you want the object to spin around. Then SHIFT + S --> cursor to selected. And then use the spin tool

It is pretty simple. If you look at your scene from upwards you see it well:

Your silhuette / cross section / whatever you want to call it is offsetted on the Y axis. As spin pivots around the 3D cursor, you want it to look like this instead:

Now the results are as follows:

Also, for practicality's sake, I would encourage you to look into the screw modifier. It does the same thing as spin, but you can edit you cross section in real time. (These settings seem to work the best with your scene.)

Also, you have duplicate vertexes (the one selected, the second and third ones from up and the one at the boundary between the foot and the upper part of the glass). You can spot them when they break smoothing and by looking at the surrounding edges. If you select only one of the pair of vertexes as shown below, the edge starting from the other one (here the edge that goes down) doesen't get a gradient.

They can do all kinds of evil (though they may sometimes be used to guide subdivision). If you try smoothing the mesh in this scene, it looks weird. You can fix this by selecting all vertexes and doing W > Remove doubles. It looks like this when fixed:

I hope this helped.


text:
Read image metadata from Python
I know that it's possible to display metadata in the Image Editor, but I need to access this info from Python, eg. in the form of a dictionary; is that possible at the moment?
If not, is there a specification for the way this metadata is stored?

See bpy.types.Image for the available information about images.
The current image of an editor can be accessed from SpaceImageEditor.image. So for a given context
context.space_data.image

Can you be more precise about what kind of metadata you are interested ?
It depends on the graphics file format (i. e. png format) and might be a question for Stack Overflow

Reading chunks from png
import os

# chunk generator
def chunk_iter(data):
    total_length = len(data)
    end = 4

    while(end + 8 < total_length):
        length = int.from_bytes(data[end + 4: end + 8], 'big')
        begin_chunk_type = end + 8
        begin_chunk_data = begin_chunk_type + 4
        end = begin_chunk_data + length

        yield (data[begin_chunk_type: begin_chunk_data],
               data[begin_chunk_data: end])

# open arbitrary pngs
blender_path = os.path.join(os.environ['HOME'], "Documents", "Blender")
pngs = (os.path.join(blender_path, elem)
            for elem in os.listdir(blender_path) if elem.endswith(".png"))

for png in pngs:
    with open(png, 'rb') as fobj:
        data = fobj.read()

    # check signature
    assert data[:8] == b'\x89\x50\x4E\x47\x0D\x0A\x1A\x0A'
    print("-" * 80, "chunks of: %s" % png, "-"*80, sep='\n')

    for chunk_type, chunk_data in chunk_iter(data):
        print("chunk type: %s" % chunk_type.decode())
        if   chunk_type == b'iTXt':
            print("--chunk data:",  chunk_data.decode())
        elif chunk_type == b'tEXt':
            print("--chunk data:", *chunk_data.decode('iso-8859-1').split('\0'))

Output
--------------------------------------------------------------------------------
chunks of: /home/User/Documents/Blender/0001.png
--------------------------------------------------------------------------------
chunk type: IHDR
chunk type: pHYs
chunk type: tEXt
--chunk data: File <untitled>
chunk type: tEXt
--chunk data: Note Test
chunk type: tEXt
--chunk data: Date 2015/08/12 17:07:41
chunk type: tEXt
--chunk data: Time 00:00:00:01
chunk type: tEXt
--chunk data: Frame 1
chunk type: tEXt
--chunk data: Camera Camera
chunk type: tEXt
--chunk data: Scene Scene
chunk type: tEXt
--chunk data: RenderTime 00:00.06
chunk type: IDAT
chunk type: IDAT
chunk type: IEND

So metadata for png is stored in tEXt chunks, separated by 0 character. See png specification

Thank you, but by metadata, I meant specifically the stamp info saved by Blender in the file header, such as Frame, Time, etc.
https://www.blender.org/manual/render/post_process/metadata.html

Nice, thanks! Now to write an equivalent for every possible format ;)


text:
Crack in my wine glass
I am doing this tutorial to make a wine glass with the spin tool. After applying the spin tool, a subdivision surface modifier and the solidify modifier my glass looks like in the image. Somehow I did something wrong resulting in a "crack" in my wine glass. When I did this process again I am sure that I set the spin tool at 36 steps and 360 degrees. What did i forget ? Hope I did not ask a question that what was already answered

here is the blender file

Try to remove doubles

I did remove doubles

Are there inside faces on the seam?

It looks like you have a face inside the glass wall.

i updated my question and added a link to the blender file

don't use the spin tool for this kind of stuff, use the Screw modifier to 'Lathe' a profile around. The benefit of Screw is that you can update your profile shape interactive, while the Spin tool is just a one-off operation that you have to undo if it isn't good.

I will try the screw modifier but now I have done this work with the spin tool  I want to understand what I did wrong ;)

I added an answer explaining what is wrong and how to fix it.

After looking at the .blend file removing doubles fixed it since you were using a solidify modifier.

It looks like you have a face inside the glass wall, the subsurf modifier does not handle this kind of non-manifold geometry very well.
Look closely, see the face within the wall.

To get rid of it just go into wireframe view and select the spare face and delete it with Del > faces.

Edit:
I looked at your .blend file and since in your particular case you are using a solidify modifier to get the glass thickness you can't directly select the offending faces and delete them.  Just go into edit mode and select all with A, then hit W > remove doubles.  This will merge the duplicate vertices along the crack.
Here is a comparison:

See how before I removed doubles, when I selected the edge loop at the location of the crack only have “tails” in one direction?  This means there are double verts at that location.

@JanScherders  I just looked at your .blend file and it seems that you are using a solidify modifier.  I just hit [W] > remove doubles and it worked fine.

you are right !! but before I used the "remove doubles" command in the tool bar and that did not remove the doubles ... Is this another command ??? Anyway, thanks

@JanScherders You have to select all first, that's all I can think of.  They are the same thing.


text:
what's wrong with my wine glass?
Still trying to model a wine glass. After applying the spin tool, removing the doubles I tried to close the holes in the stem of my wine glass. Result in the image below. After applying the subdivision surface modifier and solidify modifier the result in the other image. Somehow there is an issue in my mesh but what ? The blender file is here

I now posted two images of the wine glass after recalculating normals. Is this ok now ? Imho it still looks a bit weird ??

http://i.stack.imgur.com/gIRzc.png Normals. Some faces are pointing in the opposite direction of the surrounding faces. In Edit Mode hit Ctrl+N.

possible duplicate of Why are some faces in my mesh darker?

after recalculating normals problem still the same. should I recalculate before merging ? ...sorry... I forgot to select all. Now problem solved. Thanks !!

And also joined surfaces for subdivision modifier. The way you are trying to close it won't work. What tutorial are you following?

Jerryno: this https://www.youtube.com/watch?v=O9vDUyjt0AQ&list=PL98B6814E78D30D48&index=2 is the tutorial. but I used a background image to model the wine glass

If I want to ask somebody to explain his/her answer in more detail ... how can I do that ? Is there a mail function ? Or invite for chat ?

@JanScherders for extended comments and an actual conversation use chat.  http://i.stack.imgur.com/zFrUi.gif

Regarding non-manifold geometry, see http://blender.stackexchange.com/questions/7910/what-is-non-manifold-geometry?s=1|3.3194

The dark regions are caused by inverted normals. This is a thing many people struggle with when starting to make 3D art. Blender has a function for quickly fixing most of such cases - all you need to do is (from within Edit Mode) choose Mesh > Normals > Recalculate Outside (or Ctrl+N).
The ugly "pinching" effect is a result of all the subdivided geometry pulling in toward one point, creating a spoke-like look. This can be fixed by making an all-quad mesh instead. Try selecting that center vertex, deleting it, and instead select the remaining edges and doing a Grid Fill. Tweak the Grid Fill settings until they are to your liking.
But wait... you can't do that just yet, because there is one more problem with your mesh: you're trying to create boundaries by filling in faces to section off areas of it, but this will not work. Making paper-thin hymen-like membranous faces is a topological no-no. This results in what is known as a non-manifold mesh. To explain what does or does not encompass the definition of "non-manifold" is beyond the scope of this answer, but to sum it up, understanding that concept will enable you to create geometry that will result in the shading you want to achieve.
Your wine glass: fixed (Screen Shot - The lighting is crap, but I think it illustrates the point well enough)

Your wine glass: fixed (.blend)

And here is a side profile illustrating the boundaries of the areas you want to have thickness:

For comparison, here is the geometry you had created (after the Solidify Modifier has been applied):

I've outlined the two problem areas with the Grease Pencil tool. To sum it up, you don't want all of the wine glass to be "solidified". Think about the structure of a wine glass - the foot and stem of the glass are not hollow inside, rather they are solid glass. Yet by adding a Solidify Modifier to the entire wine glass that is what you have made - a wine glass with a hollow bottom. This is where you are having difficulty, because you haven't created geometry that accurately reflects the structure of a wine glass.
The second problematic area (which is related to the first), is that to compensate for the hollow area in the stem you tried to just add some faces between the stem and the cup (what I referred to as the "membrane"). This is where you created non-manifold geometry and further confused the problem.
Understanding these concepts will help you in every 3D sculpting project you undertake from now on, so I can't stress enough how important this is.
Here's a mediocre Maya tutorial explaining non-manifold geometry: https://www.youtube.com/watch?v=vrqxp89ilM4&spfreload=10 (sorry, it's the best video explanation I could find - of course this concept is the same whether using Maya, Max, Blender, etc.). Hopefully this will help you out beginning your understanding of non-manifold vs manifold geometry. In Blender you can highlight non-manifold geometry by pressing Shift+Ctrl+Alt+M. You can also select non-man geo by going to the menu within Edit Mode and choosing Select > Non-Manifold.

recalculate the normals helped :) the other stuff is too advanced for me, sorry.  I will try to get some info about this "non-manifold mesh" concept

hi Mentalist, a big improvement indeed !! Could you maybe explain what you did because I do these tutorials to learn something. And if I can understand what you did I can maybe do this next time myself :)

hi Mentalist, if you have time for some further explanation let me know. maybe chat ?

As per your request, further explanation added to the answer.

Many thanks for your explanation. I think I understand what you said about the problems areas. I still have to dive into the "non-manifold geometry". But I was also very interested in the way you solved these problems because I have no clue how you did that. Would be great if you would somehow make me understand that :) I also guess that the solidify modifier is not a great way to create the thickness of the glass ? perhaps there are better ways ?

ok. watched the maya video. I think I understand. thanks. but now ... how to solve that issue on my wine glass ;)

after re-reading your answer I guess I should find another solution for creating thickness of the glass. The solidify modifier is not the right tool But what is ? Still ... having created these problems I am curious how you solved them !?

I guess a better way to create the kind of thickness of the glass we want is demonstrated here : https://www.youtube.com/watch?v=9bZkivGauxY this also prevents the kind of problems you described.

Sorry if I wasn't clear - using the Solidify Modifier is totally fine... for the TOP part of the glass. What I did is apply that modifier and then delete the bottom part (the inner geometry from the stem down). Then in the bottom of the cup region I did a Grid Fill and then used Smooth to even out the vertex distribution. I hope this better clarifies for you.

BTW if you didn't want to use the Solidify modifier you could achieve about the same result by selecting all verts from the stem up, duplicating them, then using Shrink/Fatten to pull them inward, Bridge Edge Loops on the top, then Recalculate Normals. And finally, do the Grid Fill on the bottom of the cup just the same.

OK. I will try your methods on another wine glass !!


text:
Blender only sticks with one speaker?
Sometimes when I animate in blender I work with audio (mainly lip syncing characters), and I like to share it with people around me, so I unplug the headphones so they can hear it, but blender doesn't output with the default laptop speakers. I have to reload blender to get the speakers to output, but when I plug the headphones back in it keeps outputting through the speakers. It seems like blender only outputs the speaker that's available, but keeps it for the entire session. Is there a way I can change this? Here's some info on my computer:
OS: Windows 10 Home
Computer: Inspiron 3521 (Dell laptop)
RAM: 4GB RAM, 3.87 GB usable
Processor: Intel Core i3-3227U CPU @ 1.90GHz
As for the speakers, one is a Turtle Beach PX22 headset, the other is a built in Realtek (High Definition Audio). I also use Blender 2.74. Hope you can help!

does that happen using other apps as well?

@cegaton No, it only does it for Blender. This is the first time I've noticed it as well.


text:
Can't select Edge loop (Alt + RMB is failing )
On my Mac I am used to select an edge loop with Alt RMB. Suddenly it does not work in the blender file I am working on. If I open a new file, create some loops in a cube and ... I can select an edge loop with ALT RMB. Why is ALT RMB not working in this one blender file here

because you are in Face selection mode, perhaps?

yup (shame on my Face)

While in Edit Mode, you have the ability to limit the kinds of selections that your cursor can make.

When I took this screenshot it was set to Vertex selection mode here, the two others are Edge selection and Face selection.

When in Vertex selection mode you can't pick edges or faces directly.
When in Edge selection mode you can't pick vertices or faces directly.
When in Face selection mode you can't pick edges or vertices directly, as a consequence this prevents edge loops from being selected

You can have multiple modes active at the same time, which can be handy, by holding down shift and click on the icon.

Try to turn off "Emulate 3 Button Mouse"
You can find it at:
-> File
-> User Preferences(Ctrl + Alt + U)
-> Input
-> Mouse: Emulate 3 Button Mouse(OFF)
-> Press "Save user Settings"

Brilliant! That did it for me. Thank you!

Thanks. This was driving me nuts.

Now, how do I keep "emulate 3 button mouse" still having alt key working? It did in previous versions of blender, right?

A similar problem can arise when an edge is missing.  If the other answers here don't work, try to find the missing edge and fill it

get in vertex-select mode
select the missing edge's endpoints
push f to connect them with an edge.


text:
I'm confused about Links in Blender
I've got 1 scene for rigging characters & animation cycles, and 2 scenes for different settings, but the character I want to use has to be in both scenes. How does that work out? I've already animated the character for the 1st scene and I want to do it for the 2nd scene but I'm scared it'd overwrite the 1st scene keyframes. How does it work out and what should I do?

I think you'd better have the model and its rig into a group in a separate .blend file, and link it (using proxies of the group) into your scenes .blend file. This way, making a new proxy won't overwrite animations of the original model's rig.


text:
fluid in a glass
I am at beginner level. One of the projects I am doing is to create a glass with fluid. Like a glass of water or a glass of wine. Now I can find quite some tutorials on how to create the glass, but very few if any on how to create the fluid (with a realistic result). I am not looking for fluid simulations (like the water /wine flowing into the glass) but  to get something like this:

The question is not (only) about modelling the fluid, but especially how make the fluid look realistic colours, transparency, specularity, dark/light colours etc.
Maybe I should have mentioned that I am watching this tutorial. Somehow I feel that all those manipulations shown there (using Blender Render) are not fully covered within Cycles Render.

First of all I would suggest to have a look on this article http://adaptivesamples.com/2013/10/19/fluid-in-a-glass/ in order to learn how to correctly manage interfaces. They are as important as the shadeer itself.

You may do it using the Glass and Layer Weight nodes.

Model a fluid (see Carlo's link in his comment) and assign a new material to it.

Set up its material nodes as pictured below. After adding a Glass node set its Roughness to 0 and change the IOR value to something about 1.300-1.333. Adjust a Blend factor of a Layer Weight node for a different result (different blending between colors).

NOTE: I set a simple color for a background here. To make it look more realistic use a HDRI image for a background.

Note that mixing colors based on surface angle isn't an accurate simulation of absorption. It does make for a nice stylized look though :)

For any situation with multiple refracting materials that come into contact, it's important to set up the geometry to correctly simulate the interfaces between the glass and liquid. See Liquid / glass interface IOR and normals in Cycles.
Geometry
To summarize the post linked above:
Instead of thinking in terms of materials, think in terms of interfaces. In your setup, there are three interfaces:

Glass to air

Wine to air

Glass to wine

The ordering depends on the direction the normals of the faces making up an interface are pointing. For example, the way I setup the scene the normals of the glass > wine interface pointed from glass to wine. So for that interface, the IOR should be glass IOR / wine IOR.
Create materials for each interface and set their IORs appropriately. The IOR of air is 1, so division is unnecessary for the air interfaces.

For the glass > air material, you'll want to set the Index of Refraction to something like 1.45 or 1.5 (the IORs of different kinds of glass vary quite a bit).

For the wine > air material, you'll want to set the Index of Refraction to something around the IOR of water (~1.33 at 20° C).

Provided your normals are pointing from glass to wine, the IOR for this material should be 1.09 (I originally had the wrong number, please ignore the .917 in the gif).

Material
The darkening around the edges of the wine is caused by absorption.
Due to the way light refracts through the glass and the wine, light must pass through more wine near the apparent edges of the glass. This means more light will be absorbed, and less light will reach the camera, making the wine appear darker.
To simulate this, add a Volume Absorption node and plug it into the Volume output:

Note that the amount of absorption will depend on the size of your object as well as the density, so it may take some fiddling to find values you like.

This is a follow up comment to gandalf3's explanation above, there is a conflict in how ior for the surface is calculated "Provided your normals are pointing from glass to wine, the IOR for this material should be .917." but above you say "the IOR should be glass IOR / wine IOR", which is 1.0905.

Formula is [Medium with normals pointing outwards] divided by [Medium with normals pointing into it]. Air to Glass (reverse the IOR order like this Glass/Air): 1.45/1 = 1.45. Going from Glass to Liquid (normals of liquid pointing into the glass volume): 1.33/1.45 = 0.917. If you are going from Liquid into Glass (normals pointing into the liquid) then it's 1.45/1.33 = 1.09

John & @JoelArt Thanks

A couple of things to pay attention to with fluid regarding materials is the IOR (Index of Refraction). You can use a Glass Shader for most liquids. For something like milk you'll want an SSS Shader (Sub-Surface Scattering). For something like wine though, go with a Glass Shader.
Water has an IOR of 1.33 and that number is worth committing to memory (it varies slightly depending on the temperature.) Here is a list of IOR values of common liquids. Wine is not on that list but other alcohols like Vodka (1.363) and Whisky (1.356) are, so my first thought was to use a value in the 1.35~1.36 range and call it close enough... but then I decided to search "red wine IOR" and I found a super-detailed article on the optical properties of red wine.
Here's a chart:

Original URL of the chart is here.
Full article URL is here.
In short, the average Index of Refraction of red wine is about 1.345, so you can use that, or any of the IOR values from the samples on that chart.
IOR is not something to obsess over, but since you can usually find the IOR values for many common materials with some quick searching I find it's best to just look it up, plug in the number, and then move on to tweak the color and other properties of your liquid.
Another thing you might try is using a Volume Absorption Shader in conjunction with your Glass Shader to make your wine look thicker where it is denser. Red wine has sediment, so it will be a much deeper red the further in you go. A Volume Absorption Shader can help you get this look. Play with the "Density" value until you get something that looks right to you.

Finally, I realize you're not planning to do any fluid simulation, but I'll leave these two fluid sim tutorial links up for anyone who is interested:
1, 2.

Nice tips @Mentalist, but I think the OP just wants to model a fluid and give it a realistic material instead of making a fluid simulation.

Agreed. When I first read his question I wasn't sure, but I can see that now. I'll leave the links there in case someone else finds them helpful, but move them to the end of the answer as a side note.


text:
Permanent Weight Paint
[![Permanent Weight Paint][1]][1]
I have a human metarig on a playermodel
I am having problems removing weight paint errors -> I am moving the armature and then editing the weight paint, yet some points of contact still do not go away (while editing w/ weight 0.0). They show up blue but move with the armature, so my playermodel is deformed.
Also some parts of the playermodel have weight paint that I cannot change and these do also move with the armature. I have seen this with the playermodel's teeth and ribs (they have a color of pure red, weight 1.0) but attempting to change teeth and rib weight paints and\or moving the armature then attempting to re-do the weight paint doesn't remove the problem.

The problem is you have to edit your vertex group.

go into edit mode and hit the vertex groups tab.
then see all of you vertex group and experiment by means of randomly selecting vertex groups by clicking the 'select' tab while in the vertex groups sections in the properties window.
when you see a mesh that has vertices scattered and not in the location you want them to be, click 'remove' tab so blender will erase all vertices that were assigned to that group.
next group the vertices that you want to  be grouped(do it logically).

ex: hand vertices grouped, then called 'hand verts'. Head vertices grouped and called 'head verts'(or whatever you prefer).

now that your veticies are logically grouped, go into weight paint mode and commence weight painting again. (your problem should be fixed).

p.s update me if that doesn't work, or if your having issues.
happy blending!


text:
Cannot create Euro Symbol
I am working with text (standard Blender font) on a Mac. No problem with the currency symbols for yen, dollar, pound but somehow I cannot create the euro symbol. It should be Alt2 on a mac. Blender displays the euro symbol in the Tool Shelf (Edit Mode), but when I toggle into Object Mode the glyph won't show up.

This could be considered a bug, or rather a missing feature in the BFont font. You would not be wrong to submit this as a bug report to the issue tracker. It's an established currency...

Blender's default font for Text Objects (called "BFont") doesn't have the Euro symbol (August 2015). Import a different font, one that does have the Euro € symbol.
obj = bpy.data.objects['some_text_object']
obj.data.body = chr(8364) * 4

This would show 4 Euro symbols, if the Glyph is present in the table.

Hope you don't mind asking, but what font is close to BFont ? I like the "industrial" look

it's very similar to Johnston typeface https://en.wikipedia.org/wiki/Johnston_(typeface).

@JanScherders You could also try Gill Sans.

yes, Gill Sans is available as Mac font and I think I would have to buy the Johnston fonts

Gill Sans indeed comes closer