CGTalk - Mixing Textures

knight42

09-17-2002, 05:15 PM

This is the result of the workshop with Grey and myself on Sunday:

http://www.knight42.fsnet.co.uk/workshop.jpg

It looks good, but if you look carefully at the corners, theres a problem with mixing the three materials involved. Once gives the background colour and alpha map, one is a layer of grime/colour noise and one is the actual map drawing.

The prolem is I can't get the grime texture to take notice of the underlying texture's alpha channel, so you get grime where there's no map. The grime has it's own alpha channel so I can't use the same image - is there a way around this? I've tried using Mix with other textures in various combinations without success.

Jamie

Per-Anders

09-17-2002, 05:21 PM

If you're laying textures on top of each other as tags then the alpha is used in the same was as alpha in photoshop layers... i.e. it's about the objects geometry rather than the sublayers alpha, so maybe this is the problem? If it's within a fusion or the like then it's a case of increasing the contrast on the alpha till you get rid of any soft alpha... or just switching soft alpha off. Personally i woul have created the whole texture in photoshop for something like this and saved out as seperate channels... though doesn't c4d support pngs? or tiff+alpha? or something like that? anyhow. to me it looks just like the alpha isn't as clean as it should be that's all... try layering the other texture on top of the "grime" rather than the other way around in the alpha...

knight42

09-17-2002, 05:28 PM

Thanks for your answer, yes, the key is a tag applies to the geometry, not the tag underneath. I have done the textures as a Photoshop file and saved each layer, so I'll add the grime into the background colour layer, thus removing the grime layer.

Thanks

J

LucentDreams

09-17-2002, 07:14 PM

email the file to kaiskai@vfs.com or post it here, I know a handy little solution fo this one.

Per-Anders

09-17-2002, 07:26 PM

make a new texture on on top, switch transparency on (not additive, and no fresnell, full transparency), then use the sheets alpha in the alpha but inverted... this should do the trick (don't tick mix with other textures)... oh and no other channels switched on in that texture (this texture should be the last texture tag)

knight42

09-18-2002, 08:18 PM

Thanks mdme, that works perfectly! :bounce: It allows me to fiddle with the grime texture without having to keep exporting it from Photoshop.

Thanks again.

Jamie

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