Alpha textures Always Behind Grease Pencils #59979

New Issue

Daniel Oakey · 2018-12-30T08:14:20+01:00

Daniel Oakey commented

2018-12-30 08:14:20 +01:00

System Information
Operating system: Arch Linux
Graphics card: GTX 1060

Blender Version
Broken: 2.80, 266b1e2cdb

Short description of error
Import an image as plane with a transparent texture. The grease pencil object will always be rendered in front

Exact steps for others to reproduce the error

Import the provided laser.png image into blender using the images-as-planes add-on
In the Materials section of the Properties window, set the Blend mode to either Alpha Blend or Multiply
Add a grease pencil monkey (or any grease pencil object with a drawing)
Rotate the camera --> the image plane will be rendered behind the camera no matter the orientation

**System Information** Operating system: Arch Linux Graphics card: GTX 1060 **Blender Version** Broken: 2.80, 266b1e2cdbc1 **Short description of error** Import an image as plane with a transparent texture. The grease pencil object will always be rendered in front **Exact steps for others to reproduce the error** 1. Import the provided laser.png image into blender using the images-as-planes add-on 2. In the Materials section of the Properties window, set the Blend mode to either Alpha Blend or Multiply 3. Add a grease pencil monkey (or any grease pencil object with a drawing) 4. Rotate the camera --> the image plane will be rendered behind the camera no matter the orientation ![laser.png](https://archive.blender.org/developer/F6114536/laser.png) ![demo.gif](https://archive.blender.org/developer/F6114541/demo.gif)

Daniel Oakey commented

2018-12-30 08:14:20 +01:00

Added subscriber: @doakey3

Antonio Vazquez was assigned by Sebastian Parborg

2018-12-31 16:50:22 +01:00

Tomasz Kaye commented

2019-04-18 11:26:29 +02:00

Added subscriber: @info-27

Antonio Vazquez was unassigned by Dalai Felinto

2019-12-23 16:35:30 +01:00

Dalai Felinto commented

2019-12-23 16:35:30 +01:00

Added subscriber: @antoniov

Antonio Vazquez commented

2019-12-28 10:12:02 +01:00

This comment was removed by @antoniov

*This comment was removed by @antoniov*

Antonio Vazquez commented

2020-01-23 19:38:40 +01:00

Added subscriber: @fclem

Antonio Vazquez commented

2020-01-23 19:38:40 +01:00

@fclem I have tested with new engine and still does the same. Do you think this is a design limitation?

Antonio Vazquez commented

2020-01-23 19:40:06 +01:00

Test_file.blend

[Test_file.blend](https://archive.blender.org/developer/F8297481/Test_file.blend)

Clément Foucault commented

2020-01-23 19:52:23 +01:00

Yes this is because we are rendering in layers. The GPencil engine cannot know that something has been rendered and is transparent in front of it unless it has been written to the depth buffer.

There is no real workaround this it is a limitation of the way things works.

Yes this is because we are rendering in layers. The GPencil engine cannot know that something has been rendered and is transparent in front of it unless it has been written to the depth buffer. There is no real workaround this it is a limitation of the way things works.

Antonio Vazquez commented

2020-05-11 18:12:01 +02:00

Changed status from 'Confirmed' to: 'Resolved'

Antonio Vazquez closed this issue

2020-05-11 18:12:01 +02:00

Antonio Vazquez self-assigned this 2020-05-11 18:12:01 +02:00

Antonio Vazquez commented

2020-05-11 18:12:01 +02:00

This is a design limitation impossible to solve, so we can close it... no reason to keep it open.

Alex Mehler commented

2021-06-02 16:05:42 +02:00

Added subscriber: @Ulf3000

Alex Mehler commented

2021-06-02 16:05:42 +02:00

In #59979#857098, @fclem wrote:
Yes this is because we are rendering in layers. The GPencil engine cannot know that something has been rendered and is transparent in front of it unless it has been written to the depth buffer.

There is no real workaround this it is a limitation of the way things works.

now over a year later is there any idea to resolve this in the long run (like rendering gp objects with eevee )?

i dont know how you composit the things in code but just know that image planes and cartoon animation belong together like siamese twins and are the gold standard in 2d animation (and will never change)

it would be sad if the tool is just left so you can never do a full animation scene (or the bulk of it at least) directly in eevee and instead plan it around using aftereffects, still.

Since alpha clipped textures are working fine with grease pencil objects,

maybe adding a compositing step and reusing the alpha buffer of the image plane's shader onto a depth buffered(alphaclipped) version/copy of the alpha blended object/material (the one you use for compositing),

and therefor at least approximate the alpha blending.

You guys also approximate the camera depth blur so maybe that would be a solution ?

> In #59979#857098, @fclem wrote: > Yes this is because we are rendering in layers. The GPencil engine cannot know that something has been rendered and is transparent in front of it unless it has been written to the depth buffer. > > There is no real workaround this it is a limitation of the way things works. now over a year later is there any idea to resolve this in the long run (like rendering gp objects with eevee )? i dont know how you composit the things in code but just know that image planes and cartoon animation belong together like siamese twins and are the gold standard in 2d animation (and will never change) it would be sad if the tool is just left so you can never do a full animation scene (or the bulk of it at least) directly in eevee and instead plan it around using aftereffects, still. -------------------------------- Since alpha clipped textures are working fine with grease pencil objects, maybe adding a compositing step and reusing the alpha buffer of the image plane's shader onto a depth buffered(alphaclipped) version/copy of the alpha blended object/material (the one you use for compositing), and therefor **at least approximate the alpha blending**. You guys also approximate the camera depth blur so maybe that would be a solution ?

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Alpha textures Always Behind Grease Pencils #59979