Z-Transparency at alpha 1, it makes artifacts. #45367

New Issue

Mario Mey · 2015-07-07T14:46:45+02:00

Mario Mey commented

2015-07-07 14:46:45 +02:00

It happened with a MakeHuman model, till I discover this.

The faces that the normal is pointing to the camera are in front of all the faces that have in front. With alpha at 1, it should not happen this.

Open the file
Enter in Game Engine
Look at the right ear.

I think it is important now, because if I want to change it GLSL Material alpha with D511, the Transparency has to be on and, as far I know, Z-Tranparency must be active. If this method is not the suggested to be used in BGE, "Mask" does not act as a mask (*) and "Raytrace" is not something to be used in BGE.

(*) Mask is doing something weird... with alpha at 0, the object is not visible. At a low value, sometimes it mask the object that has behind (showing the world color, acting as mask), sometimes it appears as transparent... but, now, I can't reproduce the mask result. Maybe, another bug report.

70-z-transparency-artifact.blend

It happened with a MakeHuman model, till I discover this. The faces that the normal is pointing to the camera are in front of all the faces that have in front. With alpha at 1, it should not happen this. - Open the file - Enter in Game Engine - Look at the right ear. I think it is important now, because if I want to change it GLSL Material alpha with [D511](https://archive.blender.org/developer/D511), the Transparency has to be on and, as far I know, Z-Tranparency must be active. If this method is not the suggested to be used in BGE, "Mask" does not act as a mask (*) and "Raytrace" is not something to be used in BGE. (*) Mask is doing something weird... with alpha at 0, the object is not visible. At a low value, sometimes it mask the object that has behind (showing the world color, acting as mask), sometimes it appears as transparent... but, now, I can't reproduce the mask result. Maybe, another bug report. [70-z-transparency-artifact.blend](https://archive.blender.org/developer/F204216/70-z-transparency-artifact.blend)

Mario Mey commented

2015-07-07 14:46:45 +02:00

Changed status to: 'Open'

Mario Mey commented

2015-07-07 14:46:45 +02:00

Added subscriber: @MarioSottile

Porteries Tristan commented

2015-07-07 16:15:43 +02:00

Added subscriber: @panzergame

Porteries Tristan commented

2015-07-07 16:15:44 +02:00

@MarioSottile transparency mesh are rendered without depth test so it depend on the order of poly gone in the mesh.

Mario Mey commented

2015-07-07 16:29:54 +02:00

@panzergame, sorry, I don't understand... could you explain it more?

You say that it is rendered as expected? And which method should I use to modify transparency dinamically? Using Mask or Raytrace? In these cases... the name of that transparencies were wrong. It is not Nask and it is not Raytrace.

@panzergame, sorry, I don't understand... could you explain it more? You say that it is rendered as expected? And which method should I use to modify transparency dinamically? Using Mask or Raytrace? In these cases... the name of that transparencies were wrong. It is not Nask and it is not Raytrace.

Sergey Sharybin commented

2015-07-28 16:09:48 +02:00

Added subscriber: @Sergey

Sergey Sharybin commented

2015-07-28 16:09:48 +02:00

For the proper transparency working in viewport you need to sort faces, so first you draw faces with highest Z depth and then drawing faces with lower Z depth. This is something what is not implemented yet and implementing it is a bit tricky without causing slowdown.

But will let BGE guys to handle the report from this point.

For the proper transparency working in viewport you need to sort faces, so first you draw faces with highest Z depth and then drawing faces with lower Z depth. This is something what is not implemented yet and implementing it is a bit tricky without causing slowdown. But will let BGE guys to handle the report from this point.

Porteries Tristan commented

2015-09-22 17:37:12 +02:00

@Sergey : it's implemented : alpha sort mode.

Sergey Sharybin commented

2015-09-22 17:55:44 +02:00

That's only for BGE.

ronan ducluzeau commented

2015-09-22 18:15:05 +02:00

Added subscriber: @zeauro

ronan ducluzeau commented

2015-09-22 18:15:05 +02:00

It seems tha viewport transparency has a better support of Backface Culling than BGE's one.

Porteries Tristan commented

2015-10-01 12:13:26 +02:00

That's only for BGE.
@Sergey: So it's a viewport bug and there's no reason to link it with BGE, no ?

It seems tha viewport transparency has a better support of Backface Culling than BGE's one.
An example please ?

```That's only for BGE.``` @Sergey: So it's a viewport bug and there's no reason to link it with BGE, no ? ```It seems tha viewport transparency has a better support of Backface Culling than BGE's one.``` An example please ?

ronan ducluzeau commented

2015-10-01 12:26:14 +02:00

BC-z-transparency-artifact.blend
Same blend with a little bit of transparency.
With backface culling on, you don't see the ear into viewport as in BGE.

[BC-z-transparency-artifact.blend](https://archive.blender.org/developer/F241416/BC-z-transparency-artifact.blend) Same blend with a little bit of transparency. With backface culling on, you don't see the ear into viewport as in BGE.

Sergey Sharybin commented

2015-10-01 12:29:18 +02:00

@panzergame, seems i got confused at some pointwith other report. If BGE gives proper transparency order with alpha sort enabled, then this isn't a bug, just some lack of features for the realtime viewport which isn't really a bug.

Mario Mey commented

2015-10-01 16:38:40 +02:00

Gentlemen, I think here is a "bugs confusion".

Here is a screencapture of the bug I reported, been entered in BGE (with Opaque as Alpha Blend):

Here is another bug that @zeauro presented in his report. It is in Viewport and it has a fix/workaround by enabling Backface Culling in Shading. Maybe a bug, maybe not.

Also, as @panzergame mention, I tried with Alpha Sort as Alpha Blend, in this report original blend file. This mode should fix this bug, but it is not complete. Look at the left eyebrow of Suzzane:

I hope this clarifies the bug that I reported and helps to go on finding a fix.
Thanks.

Gentlemen, I think here is a "bugs confusion". Here is a screencapture of the bug I reported, been entered in BGE (with Opaque as Alpha Blend): ![mybug.png](https://archive.blender.org/developer/F241452/mybug.png) Here is another bug that @zeauro presented in his report. It is in Viewport and it has a fix/workaround by enabling Backface Culling in Shading. Maybe a bug, maybe not. ![otherbug.png](https://archive.blender.org/developer/F241454/otherbug.png) Also, as @panzergame mention, I tried with Alpha Sort as Alpha Blend, in this report original blend file. This mode should fix this bug, but it is not complete. Look at the left eyebrow of Suzzane: ![alpha-sort.png](https://archive.blender.org/developer/F241462/alpha-sort.png) I hope this clarifies the bug that I reported and helps to go on finding a fix. Thanks.

Aaron Carlisle commented

2019-06-29 02:19:37 +02:00

Added subscriber: @Blendify

Aaron Carlisle commented

2019-06-29 02:19:37 +02:00

Changed status from 'Open' to: 'Archived'

Aaron Carlisle closed this issue

2019-06-29 02:19:37 +02:00

Aaron Carlisle self-assigned this 2019-06-29 02:19:37 +02:00

Aaron Carlisle commented

2019-06-29 02:19:37 +02:00

This task is being closed because the BGE has been removed in Blender 2.8.

Sign in to join this conversation.

No Label

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Z-Transparency at alpha 1, it makes artifacts. #45367