I thought it would be so easy! :-)

I want to put a gold monogram on a transparent object so I came up with the idea of a rectangular layer on a transparent shader. I thought I would create a multichannel mixer on it using a reflective gold in one source, nothing (multichannel mixer with each channel set to none) in the other source and my bitmap of a monogram as the blender but no matter what I can get only the surrounding area gold but never the letter itself. I've tried "invert" and tried a black on white bitmap and tried reversing the sources but nothing gives me the desired result.

Could someone help?

Thanks
Ed

Here is the multichannel mixer tree expanded....

In your Source 2, set it to a 'single-channel' instead of 'multi-channel', set the channel to transparency, then set that channel to 'Value' and set the value to 100%. Currently you don't have a value set for your blender to blend. :> You could also just use your current shader with the transparency set to value-100%, but then the renderer would have to access each channel, blend the settings (0) and then display the result. Instead, with a single-channel, it only has to blend the transparency channel. I hope this helps! :>

Thanks much! I'll give it a try. I find these shader mixers a little confusing.

Here is another trick...

Thanks Mark, I couldn't get bluetone's idea to work so I'll use your way. I had tried playing around with the opacity mask but it always seemed to map to the whole object rather than the rectangular area. Does it matter what format the mask file is? Back to the drawing board as they used to say...

Hello SE, It looks like the difference between your shader and mine is the ability to chose which face is mapped to. Your's has the shape layer as a subset of the "Whole Object" instead of a different face like "Front Face 1". I suspect that it is simply the order in which the shader is built. 1. Creat the glass shader as a Multi Channel like you've done, 2. Using the mapping tool, draw the rectangle where it needs to be. This should automatically convert the shader to a Layers List shader with the newly drawn rectangle on the appropriate face. Since I can't see the extended shader tree in your sample, the solution may be as simple as dragging the rectangle layer to the appropriate face within your current shader. Always a million ways to do the same thing eh?... Mark

Yes, the problem was in the mapping. My primitive cube doesn't have any shading domains but when I changed it all to flat mapping I got it to work. There's always a gotcha:-) Now I just have to get some shading domains on my real model.... Thanks ED

Here I am again. Though successful with a cube I cannot no matter what I try, get the mapping right on my spline object.

Here is where I am stuck. I open the shader room with my spline object. I select layer shader, parametric and whole object (it is empty here for demo purposes). I create a rectangular layer on the side face (C creates the appropriate entry in the shader tree) and give it a multichannel shader color red. I then put my monogram bitmap in the opacity mask. As you can see it does not map to the rectangle but seems to be mapping to the entire object. And its sideways too.

Any ideas.. what am I missing?

My example still uses the rectangle mapping tool. To avoid distortion due to the tapering cylinder, you can draw the mapped area with the polygon tool. (note: you'll need to rotate the texture map into correct orientation) Isn't 3D modeling just the most intuitive process you've ever come across!!!? Mark

Now I'm really confused. Here's what I did and my result is quite different. (BTW this was bluetones solution) If i invert the blender color the rectangle becomes gold reflective with a cut-out monogram. I think all the settings are the same. The top level shader is plain glass and I stuck with a spline cube for ease of demo.

Spectacular! When all else fails starting from scratch is usually a good idea. Without looking over your shoulder, I'd say create a new shader an use these techniques again. Good luck.

Mark,

I finally got it! I'm a bit chagrined.. when I made my monogram the file got to be RGB and the white was not quite white. Changing it to Greyscale and thresholding it in PS did the trick.

I spent around five hours on this, those that earn their living at this have my undying respect!

I really appreciate all your time and patience. It is rare these days to receive such kind assistance but more likely here at this forum.

I am in your debt!

Glad it's working now. I feel a little dumb myself for not suggesting that you double check the texture map. It's kind of like using the trouble shooting section of a telvevision manual, "Step 1, make sure TV is plugged in." ;) When Illustrator 6 first started shipping it couldn't export a 'pure' white. I burned some hours there figuring that out before the patch fixed it. It's always something...