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Material Transparency Issues - LOGGED

by Tod · in Torque 3D Professional · 07/13/2010 (7:20 am) · 8 replies

I've been fighting with alpha transparency for some time now. I am starting to believe this is a rendering issue with T3D.

I start with a single mesh, and a single png with an alpha channel (completely opaque). In T3D I uncheck transparency in the material editor. This is the view I see. Everything looks great.

www.tglmicro.com/notrans1.png



I then check the transparency box, and now things go a little crazy. You can see culled faces appear now. What is even stranger, is I can remove the alpha channel from the png completely, and still get the same result.

www.tglmicro.com/trans2.png
www.tglmicro.com/trans1.png
I'm using T3D 1.1 beta 1.
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Torque Owner Brian Mayberry
Dead on Que Productions
#1
07/13/2010 (12:06 pm)
May be an issue with the alpha map you're using.

Try this one for grins: deadonque.com/brian/garagegames/AlphaThing.png

Torque Owner Tod
Default Studio Name
#2
07/13/2010 (9:51 pm)
Well, as indicated in the post, I even removed the alpha channel from the PNG and the result is the same. I also saved the image as a JPG and changed the materials.cs. Still the same effect.

Torque Owner TheGasMan
G.A.S. [+others]
#3
07/13/2010 (10:56 pm)
1. upload the original image to a place where we can download it: here is a place

2. Tell us your video card specs

Torque 3D Owner Caylo Gypsyblood
#4
07/13/2010 (11:16 pm)
3. Application used to create the original mesh.

Torque Owner Tod
Default Studio Name
#5
07/14/2010 (12:11 am)
In the archive, I have included the DAE, DTS, all the images used and tested, and the associated .cs files.

hair.rar

There is also a video that I recorded that shows the problem much better than an image

HairTransparency.wmv

I am running Windows 7 x64
Video: Nvidia 470GTX
Driver: 257.21 and 258.96
All nvidia global settings are left at their defaults. No overclocking either.

The app used is Blender 2.5. I am actually involved in the development of the Collada exporter for it, and have made a number of enhancements to the exporter to support T3D (with some guidance from Chris Robertson).

I am using T3D 1.1 beta with the GMK addon.



Torque Owner TheGasMan
G.A.S. [+others]
#6
07/14/2010 (1:33 am)
That's just how LerpAlpha acts in T3D. Not sure if it is a bug as I would assume that a pure white alpha would stop that from occurring.
I would use the Alpha threshold instead of the transparency check box to get your desired results.


Torque Owner Tod
Default Studio Name
#7
07/14/2010 (2:16 am)
Surely there must be a way to have an alpha channel on a texture that doesn't cause culled faces to show though. Alpha threshold really isn't an answer as that is either on/off with no semi transparency. The bottom of the hair on the back is the desired result (although detailed more), with semi transparency on the fringes.

Full Sail QA&U Lab Intern
#8
08/20/2010 (10:42 pm)
Logged as TQA-847