text:
How do I stop my glass material from bleeding into the rest of the glass?
Hard to explain, so here are some pictures. (Blender 2.8 Cycles) I made the top section orange to better show what's going on.
Here's what's happening:

Here is what I want to happen:

Here are my current node setups:

I'm trying to model textures for a plastic soda cup, like the ones you see in restaurants.

Any help would be appreciated. Am I going about this the wrong way?

Can you add a reference image of what you are trying to get?

https://www.google.com/url?sa=i&source=imgres&cd=&ved=2ahUKEwiP8Yv5h5LhAhWOqZ4KHZx0DowQjRx6BAgBEAU&url=https%3A%2F%2Fwww.homedepot.com%2Fp%2FCarlisle-20-oz-SAN-Plastic-Stackable-Tumbler-in-Clear-with-Coca-Cola-logo-imprint-Case-of-72-52203550A%2F204658596&psig=AOvVaw1h7qLd2LCw5mRDodMklO_5&ust=1553204258047516

Please use the [edit] link at the bottom of your question (https://i.stack.imgur.com/lXFuK.png) and use the tools from this site to upload images so that they are displayed as part of your question. See How to upload an image to a post?

Possible duplicate of: material showing in the wrong faces


text:
What is the difference between Reference and Background image in 2.8
In 2.8 I can add images two different ways: "Reference" and "Background".

As far as I can see both create an image that is aligned with the current view,  and both create an empty. The only difference I see is in settings for Front and Side.

When shoud I use each option and How are they different than an Empty as Image?

Both of them are different presets for an image used as empty.
There are a couple of key differences between reference and background images.
Reference images essentially act as objects. like standard objects they aren't transparent so if you pass an object behind the image then it will be obscured by the image.

Background images will show behind objects regardless of which view you see it from

Both reference images and background images will show in wireframe or solid view

Background images have backface culling

Unlike reference images if you create a background image while in orthographic view you cannot see the image in perspective view.

source: Stack Exchange

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

sort: votes


text:
How to lock the background image to the camera view in 2.8?
In previous versions of blender you could have the background image be always lined up with the camera, so it was possible to align the 3D view to match with the perspective of a reference image. Example from this link

in 2.8

Is there a setting I don't know to do this? I really would love to avoid using constraints on the empty.

See point 2 in my answer

So, @DuarteFarrajotaRamos I'm sorry I just don't get it. How do I do what is shown on the first gif? where the camera moves, but the background image stays put?

You have to use the new Camera background image feature in 2.8. The image is added directly on a camera object instead of an empty. Select a camera object and choose it from the object data tab

Let us continue this discussion in chat.

With the camera selected, find the camera settings in the Properties window.
Enable Camera background.
Select the image.

The image will now show when using camera view.

You sir, made my day! Thank you :)

Also ensure "Show Overlay" is turned on for this Camera BG to show up on 3D View. It does not seem to render however...

This so does not work for me in 2.82. I set up everything like you said but I see no image anywhere :(

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


text:
Why call calc_normals_split before acessing normals
When accessing normals from Mesh Loops, why do most export scripts I’ve seen, call calc_normals_split function? Isn’t this function used for custom normals? And why do the normals not get calculated when I call calc_normals instead?
Could someone also explain to me why the normals need to get calculated in the first place for mesh loops? Why can't they just store the normal values as do the mesh vertices.


text:
How do I select one of two imported models?
I have two OBJ files.  I Imported the first, then imported the second right after.  When I try to do a shift-drag select on the second model, the first one gets highlighted as well.  Shift drag select doesn't even work on the first model.  How do I select the second only so I can move it next to the other?
Thanks for your time!

I don't quite get what you mean by "shift drag select". I'm not familiar with this kind of selecting. You select an object by right-clicking it. Or - if you use Blender 2.80 (another missing piece of important information) - you left-click on it, depending on your settings. You drag an object by pushing 'G' on your keyboard.

Apologies, I'll include the version number on any subsequent posts I make.  And thank you for the response.  I actually just rebooted my system and when i got it back up, it was working fine.  Appreciate the time.

rebooted my system and when i got it back up, it was working fine.


text:
After baking indirect light, inside solid meshes is not dark in EEVEE
Here is the scene setup which I will explain further:

    ## Heading ##  What you see in the screenshot above:

Lit in yellow is the irradiance volume
You see a circle of lights that can be switched between spot and
point with one button. These lights are in the big box for indirect
light.  You see a small cube on a floor and there are some open walls
around the floor.
The big cube, use for indirect lighting and doesn't have to be
necessarily part of the final render.
Lit in yellow is the irradiance volume.

Scenario
When I set all lights to spot, the walls of the big box are not so much lit, and when I take a look inside the small box, it's pretty dark in there. Just a little or no light leak.
But when I set the lights to spot, the walls of the big box will be fully lit and when I take a look after baking, it is quite lite inside the small box.
Question
Is it normal?  It doesn't look like light leaks but it is quite light in there like ambient light.  Here two screenshots of what you see inside the box.  The first is baked indirect with spotlights, and the second with point lights.

Specifications
Here some specifications of the settings;
bpy.context.scene.render.engine = 'BLENDER_EEVEE'
bpy.context.scene.eevee.taa_render_samples = 256
bpy.context.scene.eevee.use_gtao = False
bpy.context.scene.eevee.use_bloom = False
bpy.context.scene.eevee.use_ssr = True
bpy.context.scene.eevee.use_ssr_halfres = False
bpy.context.scene.eevee.ssr_quality = 1
bpy.context.scene.eevee.ssr_max_roughness = 0.5
bpy.context.scene.eevee.ssr_thickness = 0.2
bpy.context.scene.eevee.ssr_border_fade = 0.075
bpy.context.scene.eevee.ssr_firefly_fac = 10
bpy.context.scene.eevee.shadow_method = 'VSM'
bpy.context.scene.eevee.shadow_cube_size = '1024'
bpy.context.scene.eevee.shadow_cascade_size = '1024'
bpy.context.scene.eevee.use_shadow_high_bitdepth = True
bpy.context.scene.eevee.use_soft_shadows = True
bpy.context.scene.eevee.light_threshold = 0.01
bpy.context.scene.eevee.gi_diffuse_bounces = 3
bpy.context.scene.eevee.gi_cubemap_resolution = '512'
bpy.context.scene.eevee.gi_visibility_resolution = '32'
bpy.context.scene.eevee.gi_irradiance_smoothing = 1
bpy.context.scene.eevee.gi_glossy_clamp = 0
bpy.context.scene.eevee.gi_filter_quality = 1
bpy.context.scene.eevee.gi_cubemap_display_size = 0.3
bpy.context.scene.eevee.gi_irradiance_display_size = 0.1
bpy.context.scene.eevee.use_overscan = True
bpy.context.scene.view_settings.view_transform = 'Filmic'
bpy.context.scene.view_settings.look = 'Filmic - Base Contrast'
bpy.context.scene.view_settings.exposure = 0
bpy.context.scene.view_settings.gamma = 1

Settings for irradiance volume;
Distance: 2m
Fallof:   0.00
Intensity:0.75
Resolution: all on 4
Clipping Start:  0.01
End:          40m
visibility:
Bias: 1.00
Bleed bias: 0
Blur: 0.2
Visbility collection: N/A
Settings for light:
Shadow: Clip sstart 0.1
Softness: 1.00
Bias:   0.2
Exponent: 2.5
Bleed Bias: 0.5
Contact shadows;
Distance 0.6
Softness: 1.5
Bias:  0.02
Thinkness: 0.2

I found the answer myself.
In the properties panel there is a tab where you can find settings for the Irradiance Volume.

Under Visibility Collection you can exclude a collection.  So In this case we add the cube to a collection (called test here) and when you bake indirect light now, everything will look the same from outside the cube, but inside the cube its now pretty dark.


text:
Uv Unwrap only shows one side

Hello guys i am unwrapping my face mesh but in UV image editor only shows one side of the mesh! how can i fix? can someone help me?

Probably because you have a Mirror Modifier active. Your figure only has that one side until you Apply the Mirror to it. Click the eye symbol on your Mirror Modifier and you will se what I mean. Hope that helps.

thank you i didnt realise at first! i toggled to object mode and applied mirror , i switched to obj mode and unwrapped again, now it showed me the two sides! thank you so much

Not a problem, I'm still a noob myself (only been learning for maybe 3 weeks.) So I figured this out like 3 days ago :)

omg you still much better than me, ive spent almost 1 year trying to model a face and still it doesnt look so good , i am still trying to figure out the best geometry for low poly to look sharp and clean for game creation but still realy hard... i just realised that we cant rely on tutorials because if you follow then it will either look like their model or turn out a monster as you are trying to model a face on behalf of other face lol  my main tutorial still blenderella , i just find very impressive the way angela models her character in every detail possible


text:
What's the most lightweight format for textures?
I want to know what's the best image format to use on textures that consumes the least ammount of VRAM during render.
I'm trying to render a scene in Blender 2.8 EEVEE but because of the textures, baking the IL takes a VERY long time and render times are around 10min mark.
I assume it's the textures that are causing this because the scene is only 1.5 million tris. But the vram consumption is 7GB but I only have a 4GB GPU (GTX970).
So I want to know which image file type will consume the least ammount of VRAM doing rendering.

The GPU does not work in terms of jpeg, png, tiff, tga, etc. During rendering every image that is used as a texture has to be stored in vram using a format that is determined by the engine, so in this case Eevee. This can range from uncompressed to various hlsl/glsl/cuda friendly compressed variants. You cannot really influence that format unless Eevee exposes its internal texture format as a config option.
The source image format you use for your textures will be converted to that internal format once, not on every frame, unless you change your source texture every frame via script or something.

I'm confused. If I use a 16bit 4k PNG it says it requires 150mb to render. But if I use a 4k jpeg it only requires 30mb. So clearly, one takes more memory then the other.

Yes because you used a 16 bit per channel color depht in your png, but only 8 bit with the jpeg. But it does not matter if its a jpeg or an png, only the bit depht matters. using this logic the "best" format would be a 1 bit black or white image, but i do not think that you like to go for that ;)

Ah I see. I saw that tga file format also gives better memory usage and has higher qaulity then the jpeg.
Is there a better file type?

Again ... the file type does not matter in terms of vram consumption. If you want to know what file format to use in general you can do that via another question ;)


text:
How to use the template_icon_view in 2.80
Here I have a simple imaginary addon that is able to append 2 cubes from a blendfile. Instead of having buttons, I want to use a preview of the cubes. Such a preview you see in asset managers. (Tried to analyse their code, but got stuck).
Here is the simple addon:
import bpy

# Here comes bl_info

# Add cube 1 to scene
class ADD_OT_cube1(bpy.types.Operator):
    bl_idname = 'add.cube1'
    bl_description = 'Adds a cube. Blue, small.'
    bl_category = 'SuperCube'
    bl_label = 'Add Blue Cube'

    def execute(self, context):
        path = os.path.dirname(__file__) + "/ojbects/cubes.blend\\Collection\\"
        object_name = "cube_01"
        bpy.ops.wm.append(filename=object_name, directory=path)
        return {"FINISHED"}

# Add cube 2 to scene
class ADD_OT_cube2(bpy.types.Operator):
    bl_idname = 'add.cube2'
    bl_description = 'Adds a cube. Red, Eating a banana.'
    bl_category = 'SuperCube'
    bl_label = 'Add Grazy Cube'

    def execute(self, context):
        path = os.path.dirname(__file__) + "/ojbects/cubes.blend\\Collection\\"
        object_name = "cube_02"
        bpy.ops.wm.append(filename=object_name, directory=path)
        return {"FINISHED"}

# The menu in the N-Panel
class ADD_MT_menu(bpy.types.Menu):
    bl_label = "Add Cubes"
    bl_idname = "ADD_MT_menu"

    def draw(self, context):
        layout = self.layout
        layout.operator("add.cube1")
        layout.operator("add.cube2")

# Register Classes
classes = (
    ADD_OT_cube1,
    ADD_OT_cube2,
    ADD_MT_menu)

def register():
    from bpy.utils import register_class
    for cls in classes:
        register_class(cls)

def unregister():
    from bpy.utils import unregister_class
    for cls in classes:
        unregister_class(cls)

if __name__ == "__main__":
    register()

I suppose we can use the template_icon_view as documented on https://docs.blender.org/api/blender2.8/bpy.types.UILayout.html?highlight=template_icon_view#bpy.types.UILayout.template_icon_view but so far I didn’t get a clue.

What's your actual goal? Is your question about how to add an object to the scene? If so, I think you're pretty close. Just display the operators as buttons and check what's the actual value of the enum is...

Goal: Instead of having buttons, I want to use a preview of the cubes. Such a preview you as you see in asset managers (Simple asset manager, Asset manager by pitiwazou, KITOPS etc).  Sorry I don't have a clue what you mean with "Just display the operators as buttons and check what's the actual value of the enum is.."  I don't want buttons.

Check out https://twitter.com/blenderdev/status/992095992269783045?lang=en

"I'm voting to close this question as off-topic because it's not a question" : more focus on correctness, protocols, guidelines than focus on trying to understand what the user is asking. For example if I was a fireman and someone calls me up saying "my house is on fair". then answer with: I don't know what you mean with fair. How could your house be on fair.
That is al right, but the fireman could include:  In case you mean that your house is on fire, tell me your address then I come and help you out. Or better: I understand your house is on fire, Am I correct? What is your address?

@batFINGER Thanks!

@RobWesseling removed the comment, I only saw the first edit with the title "Testing 123" and no content.

So I understand most effort on this forum is: tracking duplicates, mentioning users how to use Blender Exchange, etc, that kind of stuff?  Glad my account will get deleted in 21 hours.  This is not a place for me. A place for me is where people trying to understand each other. The whole setup of this Exchange is way to formal / to many rules or guidelines / protocols.

@RobWesseling - Stackexchange is not a forum. It's a q&a site. We do things here this way, because it has proven to be effective. You can take the tour, if you want to learn more about Blender Stackexchange - or Stackexchange in general.

@metaphor_set. Yes I see it's very effective now.  I know now how to use the template_icon_view in Blender 2.80.  Thanks for the solutions.

Succes guys with the proven to be effective site. My account here will be closed in one hour. Thumbs up!

@RobWesseling- k, bye.

There is an example burred in the blender source code repo
release/scripts/templates_py/ui_previews_dynamic_enum.py

tldr, its very similar to layout prop
class MyPanel(bpy.types.Panel):
    ...

    def draw(self, context):
        layout = self.layout
        wm = context.window_manager

        row = self.layout.row()
        row.template_icon_view(wm, "my_previews", show_labels=True)

        row = self.layout.row()
        row.prop(wm, "my_previews")

that doesn't clarify much so some extra notes,

the EnumProperty must be on the RNA of something built in
. i tried it on PropertyGroup and that didn't seem to work, WindowManager is used in the example
if the EnumProperty is defined as the result of a function, that function must be a top level function, methods are not allowed
if the EnumProperty is defined as the result of a function, the 4th index into the enum (the last int) is the index of this enum's value inside the whole enum, populating this number with for index, myvar in enumerate(mylist): ... ret.append((myvar, myvar, '', 0, index)) is appropriate.
if the EnumProperty is defined as the result of a function, the 3th index into the enum (the 2nd to last int) is the icon_id which can be a custom icon, be aware custom icons require care, if python's objects holding load custom icons get de-referenced that can cause icons to break.

the example linked above is quite a good example.
def get_my_enum(self, context) -> list[tuple[str, str, str, int int]]:
    if not context: return None
    return [
      ('foo', 'foo', '', 0, 0),
      ('bar' 'bar', '', 0, 1),
    ]

def register():
    bpy.types.WindowManager.my_enum = bpy.props.EnumProperty(items=get_my_enum)

I would love to find docs on what this magic tuple is, maybe its a standard enum property item but the docs don't clarify argument to attribute ordering there


text:
Check if object position and rotation are zero
I want to check if all object transforms are at zero with python. What I have so far is this:
 object = bpy.context.active_object

 if any(object.location) or any(object.rotation_euler):
    print(object.location)
    print(object.rotation_euler)

This statement any(object.rotation_euler) doesn't seem to work correctly as it returns true despite there being no rotation.
How do I change the statement to make it work?

If object has a non-zero location, the conditional evaluates to True, and the rotation of (0,0,0) will be printed. Also,this approach is very vulnerable to floating point errors. A tiny translation or rotation (resulting from say, +x and -x  rotations) may display as 0,  but not be, at high precision.

You can try rounding the values to 2-3 decimal points when comparing with 0 to make sure you're not falling victim to floating point errors:
object = bpy.context.active_object

def nozeros( vec, decimal_points = 2 ):
    ''' Returns True if none of the elements in the provided vector vec
        equate to zero when rounded by the provided number of decimal_points
    '''

    return any( round( v, decimal_points ) for v in vec )

if nozeros(object.location) or nozeros(object.rotation_euler):
    print(object.location)
    print(object.rotation_euler)

If either the location or rotation of the active object is non-zero this will script print the values of both.

suggest reducing to any(round(v, decimal_points)  for v in vec)

@batFINGER Definitely more elegant, done


text:
Why is cycles render black and white?
I have a blender project I am working on. I just started, and I made a sphere. If I switch from solid mode to rendered preview mode, I get this:

But, when I press f12 to render, I get this:

Why? Why is this happening? Please help
Here is my blend file:
https://www.dropbox.com/s/s6wato3bfp187rs/blender.blend?dl=1

It appears that you are in local view. The plane appears to not be integrated in the render layers. Perhaps you have added it in local view (it looks like a bug)?
Simply press the NumpadDivision key (÷) to exit local view.


text:
How to have a color transition material on a mesh?
Basically, I have a simple sphere and I want the the most inner part of the sphere, so the center of it, to be once color and to gradually transition to another color and it approaches the most outer part of the sphere.
Can you achieve this effect without having to rely on placing another sphere inside?

have you tried using fresnel node+colorramp?

https://blender.stackexchange.com/questions/65706/how-to-make-a-good-glow-effect-around-a-sun

Based on  Diogo Valadares's comment, you can indeed use a fresnel node + color ramp to achieve this effect. Below, I attach a fresnel node to a color ramp with a mapping node in between, giving me a transition between red and blue from the inside to the outside.

Depending on what kind of transition you want, the fresnel node may not be perfect (you can see that on the very edge, the transition is a bit too sharp), but by playing around with the constants in the mapping node you can get a sharper or smoother transition.

Thank you! I completely forgot I could use Fresnel in this way!


text:
Blender game hangs when serial read()
This is my first time using Blender. I have made a CPLD device that can transmit ASCII binary when pressing push buttons. It has been tested to work well on Spyder IDLE using pyserial.
However, whenever I run this simple test to print input from COM4 in Blender (Text.py), it hangs when I press P to run the Blender game.
import serial, bge, bpy

ser = serial.Serial()
ser.baudrate = 115200
ser.port = "COM4"
ser.close()
ser.open()

def MoveCube():
    cont = bge.logic.getCurrentController()
    obj = cont.owner
    a = ser.read()
    if (a != b''):
        print (a.decode('utf-8'))
        obj.applyMovement([3,0,0], False) #just a random testing

def execute_after_game(scene):
    ser.close()

bpy.app.handlers.game_post.append(execute_after_game)

What is going on? Thanks in advance.

From the pySerial API for read():

With no timeout it will block until the requested number of bytes is
  read.

Blender only has one thread, so blocking this thread will cause the game engine to hang as it waits for the read() command to finish.
Right now I can think of two possible solutions:

Set a timeout using timeout = x. Again from the API:

Possible values for the parameter timeout which controls the behavior
  of read():

timeout = None: wait forever / until requested number of bytes are
  received
timeout = 0: non-blocking mode, return immediately in any
  case, returning zero or more, up to the requested number of bytes
timeout = x: set timeout to x seconds (float allowed) returns
  immediately when the requested number of bytes are available,
  otherwise wait until the timeout expires and return all bytes that
  were received until then.

Create another thread and execute MoveCube() in it. This will cause ser.read() not to be executed in the Game Engines main thread and thus it will not be blocked, but the newly created thread will be blocked.

As the first suggestion is simpler to implement and uses less resources, I'd prefer it.
On another note: the bpy module is Blender's API and not the Game Engine's API. So if you want to export your game and use it outside of Blender as a standalone, I'd recommend not using bpy at all, as it will not work. See this post for more information.


text:
What is the correct measurement systems for animation?
In animation, which scale or measure system should I use? For example, If I model an entire room and plan on having a character moving about in it, should all the assets and character be done to real world values or should I use Blender units?
I'm asking this because sometimes when I make a character and scale it down to it's "real size", I sometimes have issues with simulations or hair particles because of the character being to small in the scene. Like having to use very small values to tweak values(example:o.oo5 in particle hair uniform slider instead of 0.5), which sometimes can make tweaking very finicky.
So I wanted to know which is way that is most commonly used.

You can use Blender units or "real life" units. Whatever you do (physics, particle systems, animation,...) - the important thing with scale and scaling is, that you apply it. Every object in your scene should have a scale of 1 in X, Y and Z.

That's what I do but then I have to work with very small numbers to ajust settings.

Blender units are meters. Work in real life sizes if you can.

It is unclear wether this question is about animation or simulation. You can always scale up a copy x100 and do the simulation there, then scale down the baked simulations.

The best way is using the reference unit. for each animation you should have a proper reference footage or etc.
For example you want to create walk cycle. you start to walk in your room and observe Walking variables by taking a footage from it. when you want to use that footage, you should use a measurement system With which you understand your footage. for this example metric unit maybe is the best choice.
But when you want to simulate a animation in big scale, you pick a proper ratio of a small unit that can describe the actual scale. for example the space between moon and earth is 363,104 kilometers. you can use metric unit and set it 3.63 meter to get the best result.


text:
How to create a Eye rig with cornea deformation
I'm trying to create a realistic Eye rig that uses bones instead of shapekeys to achieve more realistic results. I want the eyelids to deform around the cornea when the eye is moved around.
And while I have the eyelid being entirelly moved by bones I can't make it wrap around the eye because of the cornea. As you can see in the picture below the eyelid is clipping trough the eye mesh.

The eye was made with anatomic references and thus it's accurate, as such it has the "bulge" of the cornea.
Video showing what I want to achieve: https://www.youtube.com/watch?v=TAZIvyAJfeM
Is it possible to achieve this in Blender?

Here is a correctly rigged test character created with Makehuman:

I'm not sure how exactly this is suppose to help me. It has a setup very identical to mine except that the eye here is clearly lacking a cornea which makes it incorrect. And thus there is no clipping.

you can copy the weights and the bone position

That would do nothing. I'm going to update my question with a video of what I'm trying to achieve.

Updated question with video of what I'm trying to achieve.

I tried with the Warp modifier but it seems hard to make it work with a complexe topology, a Lattice modifier seems much more convenient:

First remove all the Copy Transforms constraints of your 3 bones (not sure why you want those).
In Pose mode, close the eyelid a bit so that you'll be able to test the modifier when the eyes are closed.
Create a lattice in front of your eye: shiftA > Lattice. Scale it down.
Subdivide it a bit, for example U and W values > 7, and make it flat on the Y axis with a V value of 1.
Give your eyelid mesh a Lattice modifier. Choose the lattice as Object.
Select your lattice, go in Edit mode, select the central vertices and make it a bit round, use the Proportional Editing / Sphere falloff type to help you.
Parent the lattice to the eye bone: ctrlP > Bone.
Now when you'll move the bone, the transformation of the eyelid will follow.
If necessary make some adjustments to the lattice in Edit mode, or scale it up or down in Object mode, play with the modifier Strength (and create keyframes if the influence changes through time). You can also limit the lattice influence on only a part of the eyelid mesh (with a vertex group that you'll set in the Vertex Group field of the modifier), etc...

Sadly, I'm not getting good results. The mesh is just being pushed away leaving gaps between the eye and the eyelids.

You need to play subtly with parameters, and also the position of the empties count, so maybe parent each of them to their own bone so that you can play on their position, there is no reason you could not make it work the way you want.

I'll experiment some more with them. But it seems that it is much harder to achieve this without shapekeys.

Yea, this really doesn't work. I tried all the values and moving things around but nothing seems to change.

could you please share this part of your file so that I can try, because I don't see how it can't work as you can set whatever factor you want: radius, strength, shape of the bump, etc...

Here is the blend file with just one of the eye sockets with the Warp setup:
https://www.dropbox.com/s/n1eg2gj4de5llgy/Eye_warp.blend?dl=0

I don't really understand some things in your setup but anyway, it looks like it's hard to make Warp work fine with a complex shape like this one, so I'm going to dig into the problem or try to find something else

What is it that you don't understand?

Ok so a Lattice may be preferable and seems to work fine, I'll try to edit my answer tomorrow  ;)

Okay. I'll patiently wait for the answer. :)

edited, I think it's much simpler with Lattice

Thank you!! This works great! I never used a lattice before, I never had a reason to use or so I thought.
Tell me, can a lattice have any shape?

No it can't have any shape, you can just choose the amont of edges loops, with the Mesh modifier you can use any sort of mesh but I don't think it can be useful for your current goal

Ah alright. Thanks for the help though!


text:
Deleting temporary mesh after extracting data
When extracting data via temporary mesh, like this:
mesh = object.to_mesh(bpy.context.scene, apply_modifiers=True, settings='RENDER')

Do I need to delete this mesh, after I'm done extracting data? Will it stay in memory after running the script?

Yes, you need to deleted them by yourself.
If you print that mesh object in script multiple times, you will find out that the name change by adding post-fix serial number to its based name as follow:
<bpy_struct, Mesh("Suzanne.002")>
<bpy_struct, Mesh("Suzanne.003")>
<bpy_struct, Mesh("Suzanne.004")>

And if you are using Blender 2.8, in the Outliner Panel, you can change display type from View Layer to Orphan Data (what an adorable name), the meshes you created will stay at there. You can pin them by pressing the cross button, making a fake user to let Blender keep the data-block.

If you need to delete it in script, you cannot del mesh since the object data-block was already binded in to bpy.data.meshes, use bpy.data.meshes.remove(mesh) instead to delete it.

Thanks for the answer! So what is the best way to delete this mesh when I'm done with it? Also reloading the file removes the orphan meshes right?

@LennyWhite https://blender.stackexchange.com/questions/27234/python-how-to-completely-remove-an-object/27235

That post shows how to delete an object, I need to delete the mesh. I tried this, and it seems to work bpy.data.meshes.remove(mesh).

The last voted answer show how to make it. The data was references in bpy.data.meshes, use the method remove() to delete it. bpy.data.meshes.remove(the_suzanne)


text:
Why does the right leg's bone in my rig move when I move the left?
For some reason, when I moved the left leg's bone, the right leg has also moved and the bone of the right leg doesn't control anything at all.
I think this is because I used Mirror to make the model, but I'm not sure I'm a complete beginner.

Most likely, this is a Weight Painting issue.
You may have some spill-over weight that reaches to the other side of your model.

To check for this, go into Weight Paint Mode and go through the Vertex Groups on one side, one by one. Check for weights on the other side of the symmetry line. You can make this visually easier, by choosing Show Active Weights > Active. With this, vertices that are not in the selected Vertex Group are shown in black.
I would suggest Normalizing your weight beforehand so that the colors you see correspond to the actual weights on the vertices.
If you don't know exactly why there would be a difference, watch this rigging tutorial. He goes into detail on the hows and whys: DanPro Skinning Basics on Youtube The series is very good.
After taking a look at your file, I discovered that your bone-naming is incorrect. However you mirrored your weights over, you ended up with one empty set (no weights at all) and one that has the weighting of both sides.
A tip for the future: if you use a Mirror-Modifier on your mesh while building it, you can leave that on through the weight painting phase and it will transfer your weight groups over automatically. That saves a lot of work. The only caveat is that vertex paint will only work on the side that has the actual geometry, not the one with the virtual vertices.

If you take a look at your bones or vertex groups, there is a series of .R leg bones. These should, of course, have their corresponding .L bones.
To fix this, I would suggest removing one half of the rig and mirroring the remaining half over a second time.
If your character was aligned head to tail with the Y-Axis, you could use the symmetrize function, since it is not, you need to do a bit more manual work.
To achieve this, you can do the following:

Go through your right side Vertex Groups and make sure the weight in them is only influencing the right side. Remove all other weight. If you have Show Active Weight on (see above) then the rest of the mesh should be black.
Delete the bones with the number suffix.
Put the 3D-Cursor on the X-Axis (Shift + S > Snap Cursor to Center)
Make sure your transformation origin is at the 3D-Cursor-
Select the bones you need to mirror, for the dinosaur those would be the arms and legs.
Hit Ctrl + M followed by Y to mirror along the Y-Axis
Correct your bone naming from .R to .L
With your bones in place, all that is left is to mirror the existing Vertex Groups over to the other side. There is a detailed guide to do this.

Here is a link to your file, I mirrored your weights over


text:
How to make individual hair strands wavy?
How to make individual hair strands wavy in Blender? I tried using the kink stuff but all that is very confusing to understand and it just makes the whole hair move in strange ways. I want to stop making the hair strands being so straight all the time. I want to add a soft wavyness to it.
How can I achieve this?

In your question, you ask "individual". But what you want is to make all the hairs of a given particle system wavy right?

I have parent particles and children particles and I want those individual strands to be wavy. The strands themselfs, instead of creating a wavy pattern with the strands.


text:
Having issues with bridging simple edge loop
first post here.
I find a strange issue and can't get it right.
I try to 'bridge two edge loops' that have the same amount of tiles. Both are round-is. See pictures..
How can i make this just work?

Cheers
Tuur

it might be a problem of normals which are not flipped in the same direction, so select all and press ctrl N

cntrl +N gives me 'new file'...

ctrl N in Edit mode  ;)

i am in edit mode.. you mean to select ALL or just all edges of the this one edge loop that makes problems

shift control + N you mean..that shows this 'Make normals Consistent' pop up thingy..   that also didn't work

in Edit mode select all and ctrl N should work, but you can go through the Mesh menu > Normals > Recalculate Outside

Ah.. ok that worked .. when i select everything as in ALL.. Thank you!

yes, that's what I said: "so select all and press ctrl N"    ;)

Ctrl+N indeed is no longer shortcut for recalculating normals in 2.8.. I can't say this was required nor useful solution to change that shortcut widely used in Blender. One more reason to mention version in the question.

Do not edit the title of the question with Solved please. If the question is solved press the green checkmark below the votes number next to the answer you found useful. Also this along many other useful things are written in the help center of this site

Your normals have different directions. You can tell by looking at the shading of the two pieces, whereas the left one has the shadow on the underside, the other one has it on the top.
To clear this up, in Edit Mode, select all faces and hit Shift + N to Recalculate the outside Normals.

Thank you both. I understand now. (Just started learning a bit)

If this helped you, don't forget to mark the question as solved.

not sure how to do that Ben.  But.. Solved!

please take the [tour] to understand how this site works.


text:
Is it there any way to view armatures in blender 2.8?
I have characters with armatures in blender 2.8 and I would like to view the armatures and change the pose. Is it possible with blender 2.8? If yes, how?

The same way as in 2.79? Turn on x-ray in the armature display properties

I found out the problem. It is actually a bug. If I open a project which I used to edit with 2.79, where armatures are hidden, and I open it with blender 2.8, the "eye" icon does not work for unhiding them. If I unhide everything in blender 2.79, save it, and open it with blender 2.8, then everything works fine. I was very confused at first, but that solved it for me.

Thats irritating, you should make sure it has been reported as a bug if you haven't already: https://blender.stackexchange.com/questions/1377/best-place-to-put-bug-reports


text:
Does the motion tracker follow a point if it changes colour throughout the video?
Does the motion tracker follow a point if it changes colour throughout the video?
Like an colour changing led dangling from a pendulum or a firework mid-flight?

Ideally you want to track objects that do not shift in shape, color or brightness. There is some room however to do some adaptable tracking.
In the tracking settings use:
Pattern Match:
Previous frame.
Enable:
Prepass
and
Normalize.
If the changes are slow, those settings might help you to track an object that changes color or intensity. Note that if the changes are too drastic from frame to frame, you will need to track until the frame where the automatic tracking stops (or fails to be accurate), then manually re-position the tracker and continue the automatic process until it fails again and so on.

Blatant quote from the manual

Pattern Match
Pattern Match controls which patterns get tracked; to be more precise, the pattern from which frame is getting tracked. Here is an example which should make things clearer.
The tracker algorithm receives two images inside the search area and the position of a point to be tracked in the first image. The tracker tries to find the position of that point from the first image in the second image.
Now, this is how tracking of the sequence happens. The second image is always from a frame at which the position of marker is not known (next tracking frame). But a different first image (instead of the one that immediately precedes the second image in the footage) can be sent to the tracker.
Keyframe
An image created from a frame on which the track was keyframed. This configuration prevents sliding from the original position (because the position which best corresponds to the original pattern is returned by the tracker), but it can lead to small jumps and can lead to failures when the feature point is deformed due to camera motion (perspective transformation, for example).
Previous Frame
Keyframes for tracks are creating every frames, and tracking between keyframed image and next image is used. In this configuration the pattern is tracking between two neighboring frames. It allows dealing with cases of large transformations of the feature point but can lead to sliding from the original position, so it should be controlled.
Prepass
Enables a two pass tracking, where the first pass is a brute force tracking of location only, and the second pass will use tracking of the full motion model refining the first pass.
Normalize
Means patterns will be normalized by their average intensity while tracking, to make them invariant to illumination changes. An example where this is useful is a scene where a marker moves in the shadow of an object.


text:
Modeling Help and Dealing with Ngon's
I am modeling a soda can and have found it increasingly difficult to deal with the high number of vertices as I collapse towards to center of the mesh. I was wondering if anyone had any advice to deal with this Ngon. Especially when trying to create finer details around where the tab should be. Still quite new to 3D modeling so any advice is very helpful, thanks!

Try to avoid elongated faces. Also look into techniques for reducing the number of connecting points, read the "loop reduction flows" section in https://topologyguides.com/

also, you have a lot of edge loops, you should try to work with much less, at least as long as you can use modifiers like Subdivision Surface


text:
Scaling/Moving doesn't work properly
recently I decided to learn and use Blender as my 3D editor
Well, all this things were working fine... until a few minutes
I made a mirrored object, but, when I press the "S" scale button, doesn't scale me proportionally

And the same thing with the "G" move button, it moves weird

And no, I didn't press the X/Y/Z keys to align it to the axes while scaling/moving
What did I do wrong or how can I return it to normal?

It depends on what do you mean by normal.. The object is mirrored. So not all mesh is edited but only real geometry which is shown with yellow color and that geometry will scale as shown above.

This is expected behavior with the mirror modifier.
You have the clipping checkbox selected on the modifier, which means that any vertices that are on the mirror plane get stuck to that plane, and can only move along it, not off of it. To disable this sticking behaviour, you can just uncheck the clipping box.
However, scaling /moving etc will still only move the actual vertices you are editing, not the virtual ones created by the modifier.


text:
When I try to render, the camera renders from the wrong position
So I am totally new to Blender and I work on blendergurus beginner series, as probably many who start with Blender. I tried to solve this now for a long time by myself but everything I read and tried did not work. Maybe you can help me :)
Somehow my camera is stuck at a weird position, if I want to render. I captured the behavior in the GIF below:
https://media.giphy.com/media/dTtyxyZqLiajfgNfUh/source.gif
(Tried to embed the GIF,but imgur is rejecting the request ¯\_(シ)_/¯)
Here are some additional screenshots of my properties, render and camera:

Start by checking if the camera has been keyframed.

Check in the outliner to see if you have another camera in the scene.  The one that is shown in the Gif, doesn't have its triangle completely coloured in - it's just the outline of a triangle. If it's completely coloured in, it's the ACTIVE camera. With the visible camera you want to render from still selected, press Control and Number Pad 0.
That will throw you into the camera view of that camera and make it the active one.

thanks for your help. It was the solution from cegaton linked above. :)


text:
How to access the search menu 2.8? (used to be spacebar in 2.79)
In 2.79 the search menu is accessed pressing the spacebar

In 2.8 the space bar is used to play the timeline.
Where is the search menu now?

To access the search menu in 2.8 press F3

Also worth noting that there is an option in the User Preferences to change the spacebar action back to search (at least in an older 2.8 build I have).

Please explain how to do this on a mac since F3 on a mac opens mission control

@MicroMachine that would be Fn + F3 (macs have the F keys the secondary buttons.)

Can someone explain how to do this on a MacBook with a touchbar since there are no F keys?

In 2.81 you can set the Spacebar Action in Preferences -> Keymap and set it back to 'Search'.

Nice first answer! Welcome to the site.

This is what worked for me (no F keys on recent macbook with touchbar)

Just to add on for Windows users, holding Fn and then pressing F3 works as well.

For me that opens the windows search menu.

You can do it on mac without touchbar by holding the fn key which makes all the F keys appear. You can also change the search menu to appear by pressing Spacebar like DanP. mentioned on top.


text:
How to specify number of cuts for subdivision modifier in python
I'm working on a custom panel in Blender. I can add a subdivision modifier with python like this:
subsurfMod = self.layout.operator("object.modifier_add", text ="Add subdivision", icon="MOD_SUBSURF")
subsurfMod.type='SUBSURF'

However I want to also specify the number of cuts. Something like this doesn't work:
subsurfMod.levels='3'

What do I have to use instead?

There is an operator that sets subdivision level for an object and adds the Subsurf modifier if it does not exist:
bpy.ops.object.subdivision_set(level=4)

You can call it with a button like any other operator:
self.layout.operator("object.subdivision_set", text ="Add subdivision", icon="MOD_SUBSURF").level=4

I understand. But I need to call this modifier with a button. So I have to use self.layout.operator.

No problem there. You can use it like any other operator. See the updated answer.


text:
How to create a seamless animation loop in Blender?
I have a small animation of a character in Blender 2.8 that is suppose to loop, however no matter what I try to do, there is always a little "hiccup" where the animation ends and starts.
Things I've tried doing:

Changing interpolation to Cyclic;
Copying start frame and placing it one frame AFTER the animation end;
Manually adjusting curves in the graph editor to make the transition more smooth.

After all of that, the animation simply does not loop correctly. The place where it starts/ends is very noticable. Despite the begining and end frames being identical, it being cyclic and having the curves adjusted.
Is there a tool, or a function or something I'm missing to create loops in Blender, or is this simply not possible to achieve?
Blend file: https://www.dropbox.com/s/nngunwosevrh5w9/loop.blend?dl=0

I'm not sure what's the problem, I can't see any hiccup, could you precisely tell what bothers you? movement of the head?

Preciselly the head. Where the animation starts/ends it looks like the head just stops for a split second or has some kind of jolt to it.

I don't see it, it looks like it's just your animation playing, and anyway if it happened there's always a way to fix it

Try render it out to see how you will perceive it where there are nothing else going on. Even when I maximize the window to get rid of the popping time line it seems to help. The brains experience of time can be easily disturbed.

Also, everything is synked at first keyframe... if you want to make it feel seemless you need to offset the motion so there is always something interesting going on.

What do you mean? All keys need to be the same on both start and end frame.

Set you extrapolation to cyclic and offset some curves so that not everything goes to a halt at the same frame. This is not a technical, usage thing but rather a subjective opinion on the animation it self so I will stop here.

A common error occurs when the first and last frame of the animation have Bezier interpolation. If the motion starts from 0, gradually accelerates, and then decelerates before the end, then a cycle will have that slowdown on the loop. You would need the animation to have a different kind of interpolation.

Hmm....So it should be more linear towards the end then?

It all depends on the motion. Another issue comes if the motion starts from rest and end in rest as well. Then there will always be a pause if the motion is cycled.

Another way to fix:
dont use double frames like all answers above already sugest.
then:
go to and select the frame where your animation starts."also leftclick onto it to make shure your on that frame.
then:
"Timeline", "Dope Sheet" or "Graph Editor"(doesnt matter realy what your using)
"Shift + E" -> Make Cyclic(modifier)

I usually key the first frame on frame 0 and output from frame 1 onward. This has to date never failed me.
Maybe your problem has a different source, share the file if you can.
Edit:
I rendered out the image sequence, then composed it. First, I assumed your hickup was just a slight buffering error from your video player, but then I compared the first and the last frame from the output, which were identical, causing a 2 frame hold.
Your first and last frame of the loop must not be identical, or you will get these slight stutters. An easy solution to that problem is to either:

push all keyframes one frame forward, so they are outside of the render area,

or shorten the render interval by one frame.

So I pulled the last frame and rendered a video. Seems gone now.
https://youtu.be/kwSuWkUF8k4

I tried that and it didn't work. I added the blend file to my question. Take a special look at the head of the character. You'll see that "hiccup" that I'm referring to.
EDIT: I'm using Blender 2.8

I don't see any hickups in the viewport. So I rendered out an image sequence and composed that into a video. This is also flawless. My guess is, you are using a viewer that rebuffers the video each time it gets played. Try it by playing this clip which is simply the comp playing twice in a row. (Up with the answer)

I think your right. I use VLC player. But amybe I should play the animations somewhere else?

You can try that. your loop file is clean if you make sure that the first and last frame are not identical, at any rate. Again, see the video link I added above.

I saw the video. It is seamless there. But you said I shouldn't make it identical?

Your first and last frame of the loop must not be identical, or you will get these slight stutters.an easy solution to that problem is to either just push all keyframes one frame forward, so they are outside of the render area, or to shorten the render interval by one frame.

Ah Okay. I think I had done that already for this animation. Anyway, I think I'll mark this as solved. Since it either is my brain acting funny or my player.
Thanks for the help!

I had the same problem and I finally found a solution. My keyframes were using Bezier interpolation by default. I switched over to Linear interpolation and it worked!
You can do this by going into the Graph Editor, then select all your keyframes, then press T  and select Linear.
Note: As others suggested you will also have to shorten the render interval by one frame.

If your first and last frames are identical, it means that you will be seing two frames in the same position, so there will be a pause.  It will be for a fraction of a second, but can still be noticeable.
If your animation was say, 100 frames long and frame 100 is the same as frame 1, then after showing frame 100, you're effectively showing the same frame again.
Loop from 1 to 99 and you're eliminating that duplicate frame.
So you either need to use one frame fewer, or render an extra frame (as your final set of keyframes), but don't use it in the actual animation.


text:
Subdividing and smoothing part of a mesh
Does anyone know, is there any way to subdivide and smooth part of geometry in mesh (in example picture necessary polygons(not all i need) are selected) without effecting  other parts and not creating weird shapes.
I append my blender file:
https://drive.google.com/open?id=1MpRbmkZtTWSo28E2p-hI0R3K8L5u8xAx

I assume you have tried Subdivide, then adjusted the smoothness slider in the floating panel (bottom left of 3D view after you hit Subdivide) ...

I would say the best is to work the other way around: create an object, smooth it, then sharp the angles you want to be sharp, either with tricks like Crease, Bevel modifier, or with additional edge loops

When I adjust smoothing in subdivide panel it starts to increase volume of some selected parts. Maybe I'm doing something wrong? I will append my .blend file. Maybe you'll fix my problem.

@edna's comment is actually the answer, in my opinion. I too have had nightmare creations resulting from using a subsurface or multi-res modifier on the whole model, and creasing, preserving sharp edges etc. It's useful when it's useful, but it adds complexity that you might not need, and it can be hard to fix when overused. Using subdivide on a selection and then adjusting the smoothness and other attributes is better for times when you need higher resolution and smoothness only for certain parts. Example:

Say I want this to look a little more like and axe. If I multi-res or subsurface modify the whole thing, I will lose all the blocky shapes, and I'll spend a lot of time editing to try and preserve sharpness. In a worst case scenario, I'll end up with lots of extra geometry that interferes with 3d printing, rendering, or whatever. Plus it's just a pain in a simple case like this. So enter subdivide:

I turn off "ngons" because if it is on I may create geometrically unsound quads. Make a few cuts, add a bit of smoothness, and now the center of the axe has a puffier shape at the top and bottom. Next, the blade:

Notice the blade is smooth, but the nearby geometry was allowed to stay simple and pointy. (Real technical terms in use here).
I can proceed like this and make any number of more complex protrusions on an otherwise simple or blocky object. Notice that the parts I left alone remain simple, while other parts have different levels of complexity as required:

I hope that helps.


text:
Unwrapping a circle into a line of segments?
How can I UV unwrap a circle (which is divided into segments) into a straight line of segments (triangles) - I can only get segments placed randomly.

I.E. a row of triangular segments with the circumference flattened into a straight line, giving a saw-tooth a pattern like /\/\/\/\/\

Can you add images to show what you are trying to achieve?

https://blender.stackexchange.com/questions/78358/how-to-straighten-curved-uvs-into-straight-belt/78376#78376

These links are not what i am looking for. I need the UV map to be a row of triangles, not quads. I don't know how to upload images. These answers give maps like this
☐☐☐☐☐☐
and I need this
//////\
Is that clearer??

@VirtualAlex You can upload images with the little picture icon at the top of the editor, see here for how to format them. Is your circle made of triangles already? Or are you trying to unwrap quads as triangles?

!([IMG]http://i63.tinypic.com/x397d0.jpg[/IMG])
Not sure if that image will work?? I have a circle made of triangles and I want to unwrap into the sawtooth pattern, not a row of quads.

please edit your post and show a picture of your object in wireframe display mode, when you'll edit you'll find a button for adding pictures

I added a pic of the error message I get when trying to run the script

The script in my answer was written using 2.8 See https://blender.stackexchange.com/questions/129473/typeerror-element-wise-multiplication-not-supported-between-matrix-and-vect  simply replace any @ symbols with * to use in 2.79 or prior.

How about the @ before classmethod? or do you mean every single instance? can I do replace all? so, 4 or 5 of them?

Ah I guess you mean just the mathematical ones, because after changing them all and NOPE, I changed the first 4 and YESSS!!!!!! OMG it worked! Genius, I just love it. I will never be afraid of circles again. I will try and post an image!!

Good one edited answer.  If you use @batFINGER in a message I will get an alert.  Most times too if it is next comment, perhaps because I had this page open in browser I didn't on this occasion.

Ok @batFINGER! And many, many thanks. On with my hat for my Sims 2 child!

Rollout Fan

Test run, cone: 12 segments, triangle fan view, default UV map, aligned to view
Script, template from  text editor > templates > python > Operator Mesh UV  Logic:

For the selected vertex, get all the linked tri faces.
Transform the selection such that vertex coordinate is zero, vertex normal
is z axis, ie translate by the vector coordinate and rotate such that
the normal is now up, using the rotation difference.
Calculate the perimeter by summing lengths of all  edges that dont
include center vertex of faces .
Much like a Mercator projection, map the angle difference of Y axis
to each transformed perimeter vertex to U.  Will be in range -pi to
pi, or -180 to 180 degrees.

To Install:

Run the script in text editor Only once to register

To Run:

In edit mode select the center vertex of the circle fan
Run the operator, F3 Circle Unfold

NOTE:
The script is written for 2.8.  Have added addon header to reflect this.
For prior versions replace @ with * except @classmethod and blender version to "blender" : (2, 78, 0) if installing as addon.
bl_info = {
    "name": "UV Unfurl Circle",
    "author": "batFINGER",
    "version": (1, 0),
    "blender": (2, 80, 0),
    "location": "View3D > UV > Circle Unfurl",
    "description": "Select circle center vertex, to unfurl UV",
    "warning": "",
    "wiki_url": "",
    "category": "UV",
}

import bpy
import bmesh
from mathutils import Vector, Matrix

def main(obj, up=Vector((0, 0, 1)), to=Vector((0, 1))):

    from math import pi
    me = obj.data
    bm = bmesh.from_edit_mesh(me)

    uv_layer = bm.loops.layers.uv.verify()
    v = bm.select_history.active
    if not isinstance(v, bmesh.types.BMVert):
        print("Not a vert")
        return False

    tris = [t for t in v.link_faces if len(t.edges) == 3]
    n = v.normal
    T = Matrix.Translation(-v.co)
    R = n.rotation_difference(up).to_matrix().to_4x4()

    # calc perimeter

    p = sum(e.calc_length() for f in tris for e in f.edges
            if not any(v in e.verts for x in e.verts))

    for f in tris:
        f.select = True
        e = next(e for e in f.edges if v not in e.verts)
        e.select = True
        ec = sum([v.co for v in e.verts], Vector()) / 2
        fu = R @ (T @ ec)
        fx = to.xy.angle_signed(fu.xy)

        for l in f.loops:
            luv = l[uv_layer]
            y = 0

            if l.vert is v:
                x,y = fx, (ec - v.co).length
            else:
                u = R @ (T @ l.vert.co)
                x = to.xy.angle_signed(u.xy)
                if abs(fx - x) >= 1.5 * pi:
                    x -= 2 * pi if x > 0 else -2 * pi
            luv.uv = (x + pi) / (2 * pi), y / p

    bmesh.update_edit_mesh(me)

class UV_OT_circle_unfurl(bpy.types.Operator):
    """Circle Unfurl
    Select circle fan center vertex
    Unfurl perimeter to U = 0
    """
    bl_idname = "uv.circle_unfurl"
    bl_label = "UV Circle Unfurl"

    @classmethod
    def poll(cls, context):
        return (context.mode == 'EDIT_MESH')

    def execute(self, context):
        main(context.edit_object)
        return {'FINISHED'}

def draw(self, context):
    ''' menu item '''
    self.layout.operator("uv.circle_unfurl")

def register():
    bpy.utils.register_class(UV_OT_circle_unfurl)
    bpy.types.VIEW3D_MT_uv_map.append(draw)

def unregister():
    bpy.types.VIEW3D_MT_uv_map.remove(draw)
    bpy.utils.unregister_class(UV_OT_circle_unfurl)

if __name__ == "__main__":
    register()

this looks a LITTLE simpler! I will also give this a go. The other method suggested (the math heavy one) gave the result I wanted but ... does life have to be that difficult??!

This should be a UV tool proposal for 2.81? Looks useful in some applications.

I get what you mean. Try marking only the interior edges as seams and unwrapping. If that doesn't quite do it, you can re-position the vertices manually from there. Normalize your UV layout. Then the length of the circumference will be 1 and the "height" of each triangle will be 1/(2pi)***(approx, see note below). This is not a good optimization of space if your entire map is just the circle, so maybe split it up a few times.
An alternative (last resort) strategy could be to mark all edges as seams and do a planar projection. Then, tediously rotate each face into the proper position. A benefit of this is that you will know exactly how much to rotate each face just from the number of triangle segments there are in the model. You have 32 triangle faces. Then each triangle has a central angle of $11.25^\text{o}$ and the 2 remaining interior angles are $(180-11.25)/2 = 84.375^\text{o}$. If you draw a picture you can see that each triangle is rotated by half its interior angle(since $84.375 + x = 90 \to x = 5.625 = 11.25/2$) plus an integer multiple of the interior angle (since each triangle is offset by $11.25^\text{o}$).
This means that in the UV editor, if you have done a planar projection, you just need to rotate the first triangle by $5.625^\text{o}$ to straighten it, and every triangle after that by $5.625 + (k-1)11.25^\text{o}$. Snap the corners to vertices.  This may go faster than you think.

First triangle gets rotated 5.625 + (1-1)*11.25 = 5.625 degrees.
Second triangle gets rotated 5.625 + (2-1)*11.25 = 16.875 degrees.
Third triangle gets rotated 5.625 + (3-1)*11.25 = 28.125 degrees.
...
32nd triangle gets rotated 5.625 + (32-1)*11.25 = 354.375 degrees.
////////
NOTE: it was incorrect of me to say that the cap's Circumference was the same as for a circle. We have a 32-sided n-gon circumscribed by that circle. We can use Law of Cosines to get the length of the edge opposite the central angle. Let that edge length be $x$ and circumradius (length of side from center of circle to a vertex) be $r$. Then
$\begin{align} x &= \sqrt{2r^2 - 2r^2\cos{(11.25^\text{o})}} \\
&= \sqrt{2}r\sqrt{1 - \cos{(11.25^\text{o})}} \end{align}$
And the Perimeter of the shape, $P$, is 32 times this:
$\begin{align} P &= 32x \\
&=32\sqrt{2}r\sqrt{1 - \cos{(11.25^\text{o})}} \\
&= 2nr\sin{(\theta/2)} \quad (^{*}\text{simpler abstraction thanks to batFINGER})\end{align}$
So if we scale the UV coordinates so that the Perimeter is "unrolled" about an edge of the UV mapping area, the ratio of the inradius, $h$ (height of the sawtooth pattern) to the Perimeter is $0.1586432873$.
$\begin{align}\frac{h}{P} &= \frac{r\cos{(5.625^\text{o})}}{32\sqrt{2}r\sqrt{(1-\cos{(11.25^\text{o})})}} \\
&= \frac{\cos{(5.625^\text{o})}}{32\sqrt{2}\sqrt{(1-\cos{(11.25^\text{o})})}} \\
&= \frac{\cos{(5.625^\text{o})}}{64\sin{(5.625^\text{o})}} \quad \text{(via other formula)}\\
&= \frac{1}{64\tan{(5.625^\text{o})}} \\
&\approx 0.1586432873 \end{align}$
Compare this to the ratio of $r$ to $C$ for any circle, which is $1/2\pi \approx 0.1595008945$.
All this means is that when you stretch out your sawtooth patter to be as long as the dimensions of the UV map, the height of the teeth should be about $0.1586432873$ times that length.

Well thank you for doing the math!!! I'll give it a go, but really - why isn't there a keyboard shortcut for this??

Idunno, try marking the seams first, maybe it will do it for you via "Unwrap" or "Smart Unwrap"? Probably not though. Then just mark all the edges as seams and planar project, rotate each triangle in the UV editor as above.

To clarify: The height of each triangle would be r * cos(theta / 2) Eg for the trivial "square" 4 segment circle, ie theta = 90 degrees, normalized with perimeter 1, would mean side length one quarter, triangle height one eighth.  The "circle" radius would be h / cos(45)   or sqrt(2) / 8   The radius or height suggested of 1 / 2pi will be the limit result as theta approaches zero, and regular ngon perimeter approaches circle circumference.

Can also use half angle sine for perimeter n * 2 * r * sin(theta/2) to avoid a lot of computation.

Cool was about to mention mathjax $p = 2 n  r  \sin (\theta / 2)$  much more readable. ... alas can only upvote once.

^agreed, then the ratio of the incircle $h$ to $P$ would be $\cot{(\theta/2)}/2n$

I'll take your word for it.  (lot of rust on my trig)  Def would use this, or similar,  to create  UV when creating a fan filled circle (via script)

Yep, verified. My calculation was off for a few minutes because I made a typo with one of the angles but it matches now. Thank you for helping me make this explanation better.

Let us continue this discussion in chat.

I thought I followed your instructions:
To Install:
Run the script in text editor Only once to register
[I copied the text you gave into the text editor (created new file and pasted it in). I clicked the Register box, and clicked the "run script" button]
To Run:
In edit mode select the center vertex of the circle fan
Run the operator, F3 Circle Unfold
[I did this but nothing happened, except the error message which I have added to this post (I think).
Can I have more specific instructions please!! Thanks.]


text:
Use images as planes with greenscreen
I thought, that I would import "images as planes" a video of a green screen explosion and then remove the green background, but I couldn't find a tutorial for it. Any help?

Don't use images as planes, use the compositor.

https://blender.stackexchange.com/questions/6942/compositing-video-layers-in-3d-space


text:
Blender objects pass through the ground
I was working on a Blender project on objects falling to the ground. I set the ground to "passive" and the objects to "active". After doing the simulation, I noticed how some of the objects just fall through the ground and the rest just land on the ground.
There were other things that I did along the way: baking the simulations and moving the objects a little higher from the ground.
I am not sure what I am doing wrong here, so I hope somebody has that kind of problem and would be able to help me :).

see https://blender.stackexchange.com/questions/40361/object-falls-though-other-objects-even-when-given-the-same-physics?noredirect=1&lq=1 https://blender.stackexchange.com/questions/1811/tips-for-making-mesh-rigid-body-collision-shapes-more-stable?noredirect=1&lq=1

I assume you haven't baked a simulation and then moved the ground, as in that case the objects would retain the baked simulation and not recalculate for the new ground position. Sometimes the simulation frames combined with the object movement means that the objects go through the floor between frames and therefore don't interact, in which case slowing down the simulation (e.g. reduce gravity or increase steps - see Sazerac's link) can solve the problem. Also try changing the Physics/Rigid/Shape to see if that solves it.


text:
Blender 2.80: Newly created object appears in unused/invisible collection - how to avoid?
I am using Blender 2.80 on Linux.
When I create an object (Add->Mesh->...) it will be put into an
collection, which is set "invisible" (not used).
How can I avoid this?
How can I predetermine where new object get inserted?

By the active group in outliner:

The white gray circle in the collection icon indicate that is the active collection now, all new object will link to there.
You can manually click on other Collection (include scene collection) to change the active collection in order to insert any thing in to desired group.


text:
How to model a pitched roof?
I need help modeling the roof part:

I'm trying to make that cube a wedge. I've tried the knife tool (both with Z and E) And I've tried all the tools in edit mode.
That "roof" I made out of planes, and I can't make them higher, they are super thin

very hard to understand what you want, maybe instead show a picture of the result you want

Hi. Please only ask one question per post.

First off there is no reason to be adding a cube up there to fill in the roof, you could simply do that (in edit mode) by adding a loop cut (CtrlR then right click or Esc to cancel the movement so the new loop jumps to the center) in the base cube then moving the new edge up to meet the peak of the roof.

If you did want a separate cube for the top and bottom of your house, you still do not need the knife tool. First scale up the cube to match the size of the bottom cube and bottom of the roof. Then simply select the top four vertices of that cube and use the two most basic modeling tools G Grab to move, and S Scale to change the size, to position it to match your roof.
I have an animated gif below.

For the "super thin" roof, you could add a Solidify modifier Planes are two dimensional, so by definition that will be super thin. You need to add geometry (by modeling or modifiers) to create that third dimension.


text:
Wedges in Blender
I'm new to Blender and 3D modelling in general. I've been trying to make a wedge in what feels like hours now with no result (using the knife tool) Anyone who can help me out and tell me how you make a simple wedge?

Is this what you want? If not, edit your question to make it clearer.

Start with a cube, then go to Edit Mode.
Select two opposing vertices, merge them with Alt M/at Centre.
Pick the other pair of vertices on that face and merge them too.
Is that the shape you wanted?

Here's a very quick way to do it:
make a cube, select one corner edge, and hit delete.  In the delete drop-down, press "dissolve edges."  You now have a wedge!


text:
How to configure this to correct translations?
How to configure this to correct translations? in I18n Branches
I found a total of 35 words or mistranslated instructions in my language, how can I configure this to correct them?
since when clicking on the place where the correction should be made and select Edit Translation, it tells me that it can not be edited, and that I need to edit in the source code which is in

all tools found in trunk / po / bl_i18n_utils dir (which is actually
  linked from Blender's source code repository)!

When you find out this, you send me to these links but I do not have the slightest idea of what to do, I really did not understand it

bf-translations - Revision 4940: /
bf-translations - Revision 4939: /
Cos

relevant https://wiki.blender.org/wiki/Process/Translate_Blender

if I understood the blender wiki I would not come here and ask for a more detailed example of how to apply it or apply it

but i solve a few days, thanks


text:
Physics simulation stops at frame 250
I am working on a gravity simulation in Blender of objects falling to the ground. The frame period starts from 1 to 250, and I started the gravity simulation by clicking "play". I somehow changed the end frame period to 300, and the gravity simulation that I did earlier just ended at 250, and I wanted it to continue to 300.
Look at the bottom of the sequence of the interface. You could see that orange line in that sequence area where the simulation took place. Once it goes over the orange line at the end, the simulation stops and it continues on to the end of the frame sequence.
Does anybody know how I can continue the simulation through the rest of the sequence?

By default simulations cache only form frame 1 to 250, you can change that in the scene >Rigid Body World > Cache


text:
Moving camera around in camera view in Blender 2.8
In Blender 2.79b, you can move around in the camera view by pressing Shift+F.  When I tried it in Blender 2.8, it doesn't seem to do anything. Does anyone know how to do this in Blender 2.8?

You can link the camera to the viewport and then rotate/pan/zoom as you are used to from the viewport - very handy!
Just

press N tp show right menu
view tab
view accordeon
view lock accordeon
check "lock camera to view"

All credits to this guy on YouTube...

Fly and walk navigation have no default shortcut.
In the view menu select fly or walk.

To navigate:

Move the mouse left/right to pan the view left/right or move it up/down to tilt the view up/down.
Move the camera forward/backward W, S.
left/right A, D.
  Jump V – only in gravity mode.
Move up and down Q, E – only in free mode.
Alternate between free and gravity modes ↹ Tab or G.
Change the movement speed: - WheelUp or NumpadPlus to increase the movement speed for this open session. - WheelDown or
  NumpadMinus to decrease the movement speed for this open session. -
⇧ Shift (hold) – to speed up the movement temporarily. - ⎇ Alt (hold) – to slow down the movement temporarily.

Read also: How can I keybind the fly navigation camera in 2.8?

Contrary to the "has no default keybind" assumption,
For non german keyboard layouts the shortcut should be shift ``  where ` is a grave accent
and shift ^  for german keyboard.
If it doesn't work please check that you are using a recent version of blender.
As per https://developer.blender.org/T55194.

To be more like other 3D software I map this to a mouse button: https://blender.stackexchange.com/a/187570/101687

Go to the view tab then go to navigation then right click under walk navigation then press change short cut and press SHIFT+F and make sure it works. you should be able to move around like you could in blender 2.7

Hi there :). Use the answer section to provide simple and detailed answer. Take a tour to understand how this site works - https://blender.stackexchange.com/tour

I used to use flight mode a lot and Blender changed the shortcut.
For 2.8+ the new shortcut for Fly Mode is Shift + "


text:
Object goes black when decimating to reduce file size
I'm trying to reduce the size of a 3D model. I tried adding the decimate modifier to all of the objects and it worked pretty well except for one.
There is a cylindrical object that goes around the couch and has about 187000 faces. When I tried decimating it, the whole object went black and it stays like that in the renders (I'm trying to render it on the web via Sketchfab).
I don't understand why a simple cylinder should need all these faces and why it goes black.

Does the object have a material?

No, it's just the number of faces and vertices that increases the file size. Isn't there a way to turn this into a simple object without so many faces?


text:
How can viewport shading functionality be used to preview render result in Blender 2.80?
I could make a glass cube in Blender 2.79b in Cycles Render. Also, I could use the Viewport Shading feature in Blender 2.79b to see my desired result.
But in Blender 2.8, it didn't seem to do anything like that. When I tried the same process in creating a simple glass cube in 2.8, it didn't seem to have the desired result. I mean, I tried using 2.8's Viewport Shading part and set it to Cycles in 2.8, but it doesn't seem to do anything.
2.8 is a little new to me. Does anyone understand my situation here? If so, how did you guys overcome this?
I just feel like 2.8 is not well-developed yet and that I should probably use 2.79b at this moment for now.

"I just feel like 2.8 is not well-developed yet and that I should probably use 2.79b at this moment for now." Bingo!

That's odd. If I set to Cycles and set the cube to glass, I certainly get a glassy material. Yours looks like it is rendered in Eevee. Are you sure you are in Cycles?

@edna Sure, I tried it in Cycles, but it doesn't seem to do it as well. Do you have any proof of how you could do this?

Switch to Cycles, Add a glass shader, press Z and set the viewport to rendered:


text:
How do I attach 2 objects if one has been appended from another scene?
I am working on a character and I made the hands for it in another file. I appended it to the file containing the character. I am trying to attach the two together, but they are 2 separate objects in the outliner.

I am trying to snap the 2 objects together similar as how it is done in the  video here at 12:38
The body has the mirror modifier applied if that means anything.
Thank you.

I may have misunderstood, but I think all you need to do is to combine the objects (select both, press ctrl-j) then adjust the position of the hand to match the arm. They probably won't snap together easily, but if you adjust the hand to match the arm, you can then use Mesh/CleanUp/Merge By Distance to merge the two once you've got the vertices close to matching.

Never mind the problem I had with the mirror modifier, I fixed that. Thanks for the tip.


text:
Changing dimensions of shapes in Blender 2.8
For anyone who is using Blender 2.8 right now, does anyone know how I can change the dimensions of the shapes in Blender 2.8.
Take the sphere for instance: I want to change the number of rings and grids on the sphere, which was a process I usually did in 2.79b. Does anyone know how I can do this in Blender 2.8?

Do you mean the original parameters when you first add an object?

cant find where to change add primitive operator properties


text:
Rendering from more than one camera view at once
Is it possible to render from more than one camera view in Blender in one time? Or do you have to do this for each camera view one by one?

There is a system in place that was initially designed for producing stereoscopic content, but was made flexible enough to basically produce an arbitrary number of views at the same time. It is called MultiView and is available in Blender 2.79 series as well as Blender 2.80. The following description targets how to set it up in Blender 2.80, as there were a few small UI changes here and there.
The .blend file I used while testing this is uploaded here:

Set the scene to use multiple views
Add as many Cameras as you need and set them up as usual.

To enable MultiView, which will render all of them in one shot, go to the Output Tab in the Properties Editor and check Stereoscopy. Then, switch the mode from Stereo to Multi-View. Deactivate the left and right camera, as they will display in red and green while rendering, following the Anaglyph standard, and their names can not be edited unfortunately. Next, add as many Camera slots as you need and name them. Note the Camera Suffix field. This is the most important one, as it will link the Camera by name to the Camera in the scene. Old-school, but that's how it is currently implemented.

Next, make sure that the scene Cameras are named according to the suffix:

At this point, you are ready to render
Hit F12 to render the scene. While the render is running, in the top right corner you have a dropdown box that allows to switch between views. This is not done automatically for you unfortunately.

Important: If you plan to composite later, it is best to use OpenEXR MultiLayer as the output format for the images, as it can store the views in one file in floating point precision, allowing for maximum flexibility in compositing. You can in this case set the Views Format to Multi-View like in the screenshot below.

You can of course use the other formats too, but then make sure that the Views Format is set to Individual. In that case, each View becomes a separate file:

Compositing
Compositing a MultiView Render Layer directly requires another node that allows you to switch between them. The View Switch node from the Converter section in the compositor allows you to do that.

External compositing software should be able to extract the corresponding channels from the MultiLayer EXR file you rendered. The design of the View Switch node is flawed in my opinion, as there is no way to switch the view with the node itself. Nor does the Render Layer node have such a dropdown box. You rather have to do this in the image editor again, like during render time. The compositing chain itself is applied to all views at the same time, which is also not ideal.
Much better choice is to use the MultiLayer OpenEXR file you produced earlier. When you load that, you can choose the view to composite from the dropdown box. It comes in like this:

But can be set to this:

Now you have access to each camera View independently and can hook up arbitrary compositing chains on each. Just duplicate the input node and set the View dropdown box to the one you need.

I was trying to do them in video forms, and it seems like the info you provided only applies to render images only. Do you know how you can do this for video forms?

Never mind, I think I know what to do from my comment above.

damn we are so close to being able to create multi-view renders all within the Compositor without having to save/load files... only missing an Input-node that would let us link each of the Multi-View render passes


text:
Fireflies. Where are the options for clamping in 2.8?
I moved on to Blender 2.8, and I'm trying to find a way to remove the fireflies in my work. Obviously, you have to use the clamping feature to reduce the fireflies, but I just couldn't seem to find it in the 2.8 version of Blender.
If anyone who is using Blender 2.8 out there right now, how do you guys find the clamping feature in Blender 2.8 to get rid of the fireflies.

i just use the denoising option and that removes the fireflies
maybe its the clamping tho

You have to be in cycles.
Then you will have the option in the Light paths section.

Most fireflies can be dealt with by clamping indirect light.
Be careful not to use very small values, as they will make the scene much darker.
Reaed: Cycles: Emission Shader does not bring enough light
Read also: What is Clamp Direct/Indirect?
and:
How to reduce fireflies in Cycles?
What is the Reason Cycles Creates Incorrectly Colored/Firefly Artifact Pixels?
Managing/Reducing noise in a night scene


text:
Blender is just rendering a png I added as a plane instead of what the camera sees
When I press render, it doesn't render what the camera sees, but instead a png image that I added as a plane (specifically a very heavily edited picture of my face).
I made sure the camera is set to the actual camera in the scene settings, and not the png.
I've also tried moving, deleting and re-adding the camera and nothing has helped.
Here's a Gdrive link to the file: intro.blend

In the future please add images of your settings and add more information on your project instead of asking users to download your files.

You have selected the png file to be the source for the output (composite)

Select the rendered result.

Thanks, sorry about not dding pictures, I didn't realize that was discouraged. I'll use that advice in the future. Unfortunately, doing this just results in a black screen being rendered.

You have to render, so that the compositor has information. Press F12 to have an image


text:
Filling objects into a container: it's taking a while
I tried making small objects fall into a container in Cycles, but by doing so when hitting the Animation Player feature, it just seems to take a while and like a long time. Is this normal in Blender? If there is a problem on the other hand, is there a way to make it go faster when making them fall into the container?

What are your computer's specifications? Generally, it's pretty common since the physics calculations require extensive computation. You should bake your animations so you can play it a bit faster. More info https://docs.blender.org/manual/en/latest/physics/baking.html


text:
Objects stuck in solid mode?
I can't figure out what is causing this I tried removing the materials for the objects as well as re-assigning new materials and flipping normals I don't know what is causing this issue for the model.
The head seems to be working like it should but the body doesn't turn white in textured mode or black in material mode. I'm using default blender render

Select the stuck object and look at maximum draw type (object tab, in the display section).

Thank you so much!

Extending lemon's commented.
An object can be restricted to a lower display mode.
In 2.79 it is set in the Properties Panel in the Object tab under the
Display section.

The Maximum shading mode to display in the 3D View. This can be useful if you have a high-poly object that is slowing down performance.

In 2.8 the term is Display As.


text:
how to understand what happens when you duplicate frames
how to understand what happens when you duplicate frames
for example I have this animation and select everything in the 3d view, then press copy and then move on the timeline to the place I want to place them and press paste.

the copied keyframes include the first keyframe that in my walking animation will be the last one
then paste everything marking the keyframe 40 as a place and
I suppose that the kyeframe 1 is left over the keyframe 40 and
I do not understand if it is overlapped or replaced or they will remain as two
keyframes in the same place on the timeline,
and I guess this ruins my animation cycle because what
I want is to lengthen the cycle of walking with fluids and smoothness

then I assume that if I have 40 keyframes starting the copy in keyframe 2 and I must select 30 and paste them in 41 so that the number 40 in the duplicate becomes the number 80
How can i solve this problem ???

could you please share your file, at least the armature, so we can try to do what you're trying to do, because right now it's hard to understand...

what is difficult to understand? the question refers to knowing if I duplicate the frames and paste them next to the ones I have creates a double frame? like when 2 vertices are ensiled and in the same vector and you need to apply the doubles to be just a vertex and eliminate the doubles that are occupying the same vector and join to form a single TRIS


text:
Objects are 2 different sizes but scale says they're the same
While trying to make my dude I had to scale him up so he would align with the reference image I'm using. But the little box that shows his size and position says hes 2.202 (on all axes) , while the armature that is also 2.202 is smaller.
If I scale the armature it comes out at the wrong size, and if I apply scale to the character he will just be the same size except the scale is reset to 1.
I really don't want to recreate the armature since getting his finger bones was an absolute pain ☹.
Here are images of the said things.

ok I guess i will change it...

Read: why do measurements change when switching from global to local in edit mode and Why do the measurements of this object seem erroneous?

As a beginner, I didn't get why strange things were happening, until I discovered Object | Apply | Rotation and Scale.  It then became my "goto" thing for fixing up weird problems.  In about 99% of times, it does the trick.

Basically, object scale and Edit Mode scale are two different things. You likely scaled him in Edit Mode, so the object mode scale does not change. I would scale one of the two objects back down in Edit Mode (Tab) until they match up. Hope this helps!

ok I resized it a bit and I guess i got it the correct size.


text:
How to render an animation with Render Layers?
So, I heard some people recommending rendering an animation in layers to render faster and save on memory.
So I have attempted a simple scene(.blend included) where I have three Render Layers. One called "Plane", another called "Objects" and finally one called "Cube".
The scene has a plane to act as a floor, some objects and one of them is a cube. The cube has a simple animation of moving from one side to the other with it's shadow interacting with the floor and the objects. All of these elements are on their own render layers.
When I tried to composite them, I noticed that the Ico-Sphere is no longer clipping trough the floor(plane) which is not what I want.
This picture shows you what I mean. The Ico Sphere is suppose to be going trough the plane but when I composited it put it on TOP on the plane which is not what I want.

What I also tried to do was to render it out as an EXR file but the files came out black showing nothing at all.
Any further help on this would be very appreciated.

It is possible and advised, you should probably render frames to Multilayer EXR. See https://blender.stackexchange.com/questions/16152/save-all-render-passes-to-a-single-exr-image/18406#18406 and https://blender.stackexchange.com/questions/3470/what-file-format-should-i-use-for-rendering/3472#3472 If these don't answer your question please edit your post and add more information so we can reopen it

Unfortunately that answer wasn't enough so I've added more information to my question so you can reopen my question.

because the icosphere and the plane are in different layers, they dont interact with each other. You can either:
1- have the plane and the sphere in the same layer
2- duplicate the plane and move it to the object layer, and make it a shadow catcher and a holdout in Object Properties > Visibility


text:
How to erase any residual keyframes from a .blend file?

This is something annoying because it always happens at some point, since I know Blender in version 2.5x I have always wondered how to delete those keyframes that are lost and do not appear or are assigned to any object or value or constant of your blend file, and that you never find and although they seem harmless they always end up causing you problems to export your model to some other game engine platform.
Any suggestion of how to erase these keyframes? Some script or something in the file that you should delete???
empty.blend download

Have you tried the Outliner?  Press the plus sign at the left of the object's strip to see the 'Animation' strip.  Right click on that and select "Clear Animation".  If that doesn't do it, save the project, exit Blender, delete any cache folder/files you see in both the project folder, or Blender's Temp folder.  Fire up Blender again.  Also check you're not using baked animation somehow.  Could the object be linked to another somewhere?  Right click the Outliner strip and "Unlink".

no, none of that works, since blender use has always had that problem at some point fuck your file with that frame and you never find a way to eliminate it, in blender development they never tell you how to analyze the file from outside or externally to search the problem and there is no relative information here, and here the administrators are annoyed and it rots the soul that you ask things related to the source code and you start being harassed

I'm not new to blender enough, if you want to solve it with your suggestions here at the end of the post is the file,

I tried that link and ended up on a Google page for first aid kits!.  Nothing downloaded either.   I use Vers 2.77a because it's stable and in my opinion, downright fantastic - usable and predictable - better the devil you know :)  I appreciate your frustration - I've encountered similar in earlier versions and it's taken some time to eliminate or work around these glitches. Most often it's something I've done.

@Edgel3D sorry in the original edition erre the syntax of the link, try now and you can download it

Downloaded ok this time - have posted an answer...

I got rid of it but using vers 2.77a.  Let's hope it works in your version...
-===============-
The problem was a grease pencil hangover and it's slot that was still active.
Procedure to rid yourself of that pesky keyframe...
Zoom in a bit to see the G/pencil drawing south of the grid.
Goto Edit mode and press A.  The GP points will all hilight
Delete them with X.  (points)
Press N to open the 3D viewport's properties and delete the Grease Pencil slot.
Untick the grease pencil's box.
The keyframe will still be there.
Save the file as something else and the keyframe should disappear when the 3D widow updates.
If not exit Blender and reload.

and to think that in blender they must have told me to change to 2.8 ajajaja I appreciate the suggestion but to my 2.8 I do not like it or I contemplate it as an option it is scare ehe unstable

Thank you very much

No problems mate - Happy Blending...

this might work for you in the python console..it loops through every keyframe in the scene and deletes them..
import bpy
for a in bpy.data.actions:
    bpy.data.actions.remove(a)

this works to eliminate lost frames of a very large scene that I had abandoned, it did not occur to me to use peiton jajajaa now more than the solution you reminded me so that it has integrated that ugly pseudo language called python, my programming language is c, c ++ c # y others of high level, I try not to contaminate myself with python but because sometimes it is useful although I do not like

Thank you very much

I actually tried this in the attached .blend file and it didn't seem to work, but will leave it incase others find it useful...
similar to Edgel3D's answer, I was able to delete the keyframe by going into edit mode then hitting A, and clicking "Delete All Active Frames"

grace pencil does not give problems, the problem is in how blender joined it to itself, and never make a debug worthy of respect and these errors of novice programmer of people who are supposed to participate in code quest u code summer are quite criticizable but that bothers you, read this
https://developer.blender.org/T66634