Transparent Shadows using Cycles may cause shadows in some condition #41052

New Issue

Matt Outlaw · 2014-07-13T06:11:05+02:00

Matt Outlaw commented

2014-07-13 06:11:05 +02:00

System Information
Windows 7 64 Bit, Nvidia GEForce gt540m

Blender Version
2.71 9337574

Short description of error
Cycles Render issue
If you have an object that has multiple materials that overlay, and the top material is set to Transparent BSDF, and the material underneath has the part of its material transparent by using an opacity map, the top causes a shadow on the bottom, even though Transparent Shadows is checked on both.

If the latter is just fully transparent, there is no issue.

Exact steps for others to reproduce the error
This was exported from one project to blender, using proprietary objects, so I cant pass them along in a blend file. Here is a very descriptive picture, hopefully it gets what is needed. Of course, don't rule out user error. :)

**System Information** Windows 7 64 Bit, Nvidia GEForce gt540m **Blender Version** 2.71 9337574 **Short description of error** Cycles Render issue If you have an object that has multiple materials that overlay, and the top material is set to Transparent BSDF, and the material underneath has the part of its material transparent by using an opacity map, the top causes a shadow on the bottom, even though Transparent Shadows is checked on both. If the latter is just fully transparent, there is no issue. **Exact steps for others to reproduce the error** This was exported from one project to blender, using proprietary objects, so I cant pass them along in a blend file. Here is a very descriptive picture, hopefully it gets what is needed. Of course, don't rule out user error. :)![BlenderBug.jpg](https://archive.blender.org/developer/F97643/BlenderBug.jpg)

Matt Outlaw commented

2014-07-13 06:11:05 +02:00

Changed status to: 'Open'

Matt Outlaw commented

2014-07-13 06:11:05 +02:00

Added subscriber: @outlaw3d

ronan ducluzeau commented

2014-07-13 08:39:39 +02:00

Added subscriber: @zeauro

ronan ducluzeau commented

2014-07-13 08:39:39 +02:00

I can't reproduce with a simple .blend made from scratch.transparent_test.blend

Problem could be related to your images, your scene setup...

Before problem can be accepted as valid, someone should be able to reproduce it.
Try to make it obvious on a simple .blend from your own creation.

I can't reproduce with a simple .blend made from scratch.[transparent_test.blend](https://archive.blender.org/developer/F97652/transparent_test.blend) Problem could be related to your images, your scene setup... Before problem can be accepted as valid, someone should be able to reproduce it. Try to make it obvious on a simple .blend from your own creation.

Bastien Montagne commented

2014-07-13 10:16:23 +02:00

Added subscriber: @mont29

Bastien Montagne commented

2014-07-13 10:16:59 +02:00

As @zeauro said, we need a .blend file to reproduce the issue.

Matt Outlaw commented

2014-07-13 17:07:36 +02:00

Thanks for setting that up, I would not have been able to do it. I added another plane, so that it is more like my example. I could not replicate exactly, but there appears to be an issue, I have attached the updated .blend and a render. It could be this is what I am seeing on a different/bigger setup.
transparent_test.blend

Thanks for setting that up, I would not have been able to do it. I added another plane, so that it is more like my example. I could not replicate exactly, but there appears to be an issue, I have attached the updated .blend and a render. It could be this is what I am seeing on a different/bigger setup. [transparent_test.blend](https://archive.blender.org/developer/F97712/transparent_test.blend) ![TransparencyIssue.jpg](https://archive.blender.org/developer/F97714/TransparencyIssue.jpg)

ronan ducluzeau commented

2014-07-13 18:59:54 +02:00

I did not do a mistake, intentionnally.
But painting the transparency map, brush stroke was occluded by transparent higher part of mesh in 3D View.

Maybe you did same error.
After correcting map by painting it in Image Editor; error dissapeared.
corrected_map.blend

I did not do a mistake, intentionnally. But painting the transparency map, brush stroke was occluded by transparent higher part of mesh in 3D View. Maybe you did same error. After correcting map by painting it in Image Editor; error dissapeared. [corrected_map.blend](https://archive.blender.org/developer/F97727/corrected_map.blend)

Matt Outlaw commented

2014-07-13 19:48:20 +02:00

Oh, OK, I will try and replicate using this some more, if I can't then there must be some scene issue I am having. I will report back within 2 hours...

Matt Outlaw commented

2014-07-13 21:03:20 +02:00

This must be a OBJ or UV mapping error somehow. I have made every material on the object a simple Transparent BSDF, and I am still getting those shadows. It is only when I delete the object itself that the shadows are removed. I am sorry to have spent your time on this. I do not know the cause, but since it cannot be replicated, it must be in the design of the OBJ I suspect.

Bastien Montagne commented

2014-07-14 00:54:32 +02:00

Changed status from 'Open' to: 'Archived'

Bastien Montagne closed this issue

2014-07-14 00:54:32 +02:00

Bastien Montagne self-assigned this 2014-07-14 00:54:32 +02:00

Bastien Montagne commented

2014-07-14 00:54:32 +02:00

Ok, closing this one for now, then. :)

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Transparent Shadows using Cycles may cause shadows in some condition #41052