For some odd reason, I cannot get a transparency to work correctly after adding a P5 Material. The transparency is set to 100%, the falloff and edges to 0%. Oddly, I got one transparency to render correctly, but subsequent renders show the bodysuit in its entirety. Is there any way to fix this?

Try setting falloff to 100% and make sure the specular colour is pure black?

It could be just a "low on memory error". If not, I would suggest that you connect your transparency-map to the "Specular Value"-channel.

I'll have to wait till I get back home to look at the specular color. I just tried a few things with a prop. Keeping the transparency falloff at "0" is necessary, but a white specular color will still leave a ghost image, which is what I'm seeing in my render. Black specular with 0 falloff is invisible. Black specular with falloff=1 still leaves a ghost of the catsuit. I'm starting to think that trying different materials changed the specular color and going back to the material I wanted didn't change it back to what it was and that's why the first render was okay. I've still got to play around with how to get the transmap to be smoother during a render, but finally decided that the rough edges work better with a fur outfit.

Is your transmap a JPEG? If your intent is for an essentially black and white transmap, all-or-nothing with hard egdes, JPEG compressing can mess with the edges. Try saving the transmap as a PNG.

I've never been able to make transparency maps work with P5 materials. If there's a way to make it work, I'm dying to know!

You can't make transmaps work with P5 materials? I don't get it. Can you show an example?

This is Mace's male cheongsam - a trans map and texture for the V3 morphing fantasy dress (on her bishonen for the V3 male). The left pic is with Mace's textures. The right pic is my attempt to apply the "blue satin" P5 material from RDNA. The yoke is how the material is supposed to look (no trans). The neck, which has the transmap applied, is the problem.

I wonder if it might be that P5 "feature" where it "remembers" what textures you used before.

Any material that uses specularity like the satins do require that you use a specularity map to only apply specularity to the parts that are opaque. Try applying the transmap as a mask to the specular value channel. The rule is, what's white will show specular, what's black won't. If the material uses alternate specular, you have to the do the same thing for the specular value there.

Changing the specular color to black had no effect on the catsuit. It's still leaving a membrane appearance to the transparent areas of the render. I guess I'll have to try attaching the transparency map to specular, but it's too late for that tonight.

*Try applying the transmap as a mask to the specular value channel.*

There's still, as Gagnonrich says, a "membrane" appearance. Kind of interesting effect.

Are you sure the black parts of the transmap are 100% black?

Yup. It's the same transmap that works fine with the P4/PP textures.

You must plug the transparancy map into the VALUE channel of ANY and ALL active specular, reflection or refraction channels in order to totally eliminate the ghost effect. And Kiera is correct that if the black in the transmap is not RGB 0,0,0 then you might still see some effect.

As I slap my hand to my forehead, I've solved my particular problem and it was a mistake on my part that I forgot till I went backwards a few steps to try to figure out what went wrong. I reloaded the catsuit, rendered it and found the same problem--and it hadn't been a problem before. When I looked at the transmap, I realized that I made a change to the map, resaved it, but forgot to delete the template layer that I was using as a guide. I wound up saving a transmap that had a slightly opaque template on it and that's what was causing me all the trouble. That doesn't solve randym77's problem, but mine's now fixed and I can get back to pulling together the rest of the image and not keep spinning my wheels.