PDA

View Full Version : Self illuminated texture maps with AlphaChannels


LoveFest
08-22-2011, 04:41 AM
I can't figure out how to have a self-illuminated texture show through an alpha channel in Maya.

It's easy as pie with the Unreal engine (2.5x). Maybe, if I show you what I'm doing, it will help.

Faking self-illuminated textures.

It works just like a layer in Photoshop. With Unreal you can use an alpha channel to have one surface show through another (like layers in PS).

http://img27.imageshack.us/img27/7151/xansodaunlitalphatextur.jpg (http://imageshack.us/photo/my-images/27/xansodaunlitalphatextur.jpg/)

Same thing here in Unreal Tournament: http://img856.imageshack.us/img856/4418/alphachannel.jpg (http://imageshack.us/photo/my-images/856/alphachannel.jpg/)
An alpha channel is used to allow the unlit (faked self-illuminated) texture to show through, allowing two textures to work as one.

I'm trying to get the same effect with a bullet in Maya (see example of effect below). The tip is self-illuniated. Use an alpha to allow the white hot texture (set to full incandescence) to show through the MR Mia_Material (Copper/Chrome) material.
http://2media.nowpublic.net/images//59/90/5990552f2864211e100d042897952c97.jpg

tobbew
08-22-2011, 08:35 AM
Mia_material_x has the additional color slot under advanced which is the same as incandescense. You could use the mia_light_shader texture in that slot if you want more control over contribution to reflections and FG.

LoveFest
08-22-2011, 09:41 AM
Mia_material_x has the additional color slot under advanced which is the same as incandescense. You could use the mia_light_shader texture in that slot if you want more control over contribution to reflections and FG.

Thanks tobbew for responding. :) I'm looking at the additional color slot, but have no idea what to do with the mia_light shader (or even sure I'm looking at the right one). I tried playing with it, but I'm pretty lost on how to get the same affect as DJ way

I got the tip to glow by following the tutorial "Creating glow maps for the cooling tubes:" It's almost there, but the mia_material I added(using presets, 50% chrome & 50% copper) to the color input of the Maya phongE material causes the color to desaturate. I can't get the color back up, even by making the mia_material's color darker.


http://s2.postimage.org/1iwxjllic/white_hot_bullet_tip_maya.jpg (http://postimage.org/image/1iwxjllic/)

Azrail
08-22-2011, 10:33 AM
You can use the mib_color_mix to mix your shaders - here is some concept network:

mia_x1.result -> mib_color_mix1.color_0
mia_x2.result -> mib_color_mix1.color_1
blendMap.outAlpha -> mib_color_mix1.weight_1
mib_color_mix1.message -> shadingGroup.miMaterialShader
mib_color_mix1.message -> shadingGroup.miShadowShader

key thing is the Num attribute of the mib_color_mix equals the number of input conections or sometimes it doesn't work properly.

tobbew
08-22-2011, 10:48 AM
If you want the tip to glow just use your alpha channel for your lighting in the additional color slot. Otherwise it seems you got another possible solution.

LoveFest
08-22-2011, 10:52 AM
You can use the mib_color_mix to mix your shaders - here is some concept network:

mia_x1.result -> mib_color_mix1.color_0
mia_x2.result -> mib_color_mix1.color_1
blendMap.outAlpha -> mib_color_mix1.weight_1
mib_color_mix1.message -> shadingGroup.miMaterialShader
mib_color_mix1.message -> shadingGroup.miShadowShader

key thing is the Num attribute of the mib_color_mix equals the number of input conections or sometimes it doesn't work properly.
Hi Azrail, Thanks for responding.

Where would I connect the mib_color_mix? Please take a look at the thumbnail below. I showed how far I got. Thanks :)

http://s2.postimage.org/1iwxjllic/white_hot_bullet_tip_maya.jpg (http://postimage.org/image/1iwxjllic/)

LoveFest
08-22-2011, 11:22 AM
Mia_material_x has the additional color slot under advanced which is the same as incandescense. You could use the mia_light_shader texture in that slot if you want more control over contribution to reflections and FG.
That worked! I didn't even need a grey scale. Just used the color map. I can't believe that was easier than Unreal 2.5x. Thanks tobbew. You're golden, man.
http://s2.postimage.org/1jbehvx2c/white_hot_bullet_tip_ryan_johnsond_copper_color.jpg (http://postimage.org/image/1jbehvx2c/)

The only other question I have is how to fix the reflected striation running down the bullet. I have a real one in my hand and they don't "stretch" the clouds or the reflections in the room like pulled/stretched streaks. Would a cube map work better than using straight reflections from an image based map in Mental Ray?

LoveFest
08-22-2011, 11:45 AM
You can use the mib_color_mix to mix your shaders - here is some concept network:

mia_x1.result -> mib_color_mix1.color_0
mia_x2.result -> mib_color_mix1.color_1
blendMap.outAlpha -> mib_color_mix1.weight_1
mib_color_mix1.message -> shadingGroup.miMaterialShader
mib_color_mix1.message -> shadingGroup.miShadowShader

key thing is the Num attribute of the mib_color_mix equals the number of input conections or sometimes it doesn't work properly.
Azrail, you're amazing, good! I just went to your site.

tobbew
08-22-2011, 12:44 PM
The stretching could be due to the anisotropy settings in the mia_material and could then be easily changed. It could be due to distortion depending on your environment setup. Preferrably use a spherical hdr in the native ibl.

CGTalk Moderation
08-22-2011, 12:44 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.