I don’t know, it’s not too dire now that I got it, it took me a while to figure out and it keeps doing its cruddy black letter borders from time to time, and then restarting fixes that mostly. I think a cool constructive thing would be either a Palette object that takes care of text in 3D with transparency once and for all (textSOP and TOP approaches with a complex MAT like Phpng or PBR maybe), or a tutorial with a solid sample file and the right material settings. Text is such a classic and necessary tool that it would really use a high-level/best practices treatment for everyone so we wouldn’t have to stumble on it anymore. Lots of graphic designers and other TD video users might have a need for this feature as a staple I imagine.
Anyhow, I attached my file cleaned up, I removed the messy Phong MAT that I had taken as far as I could but that had popping issues when ranging alpha from 0 to 1 and other problems listed above. I left a Constant MAT there which makes my life simpler. And it will either have nice text transparency all along with the Alpha slider range or it will have the black cruds around the letters. As I said, restarting the file works for me, and then doesn’t and then eventually does. See it working here in opposition to the previous screenshots. Use the slider to see how smooth it should get.
File is attached here:
transparencyText2.zip (13.4 KB)
My TD version: 2021.13610
MY graphics card: 3090RTX
BTW @malcolm and @ben’s recommendations worked close but not not100% for me, see my Phong MAT and comments on Apha slider in the previous file.