#Opacity Hell
9 messages in this thread
Gary,
I'm still having problems with the opacity maping in 3ds3. Several
weeks ago I uploaded a sample project to demonstrate the effect. To sum it up,
under certain conditions (I'm not sure what they are) opacity mapping fails —
ie. areas that should render transparent do not. Sounds like a case of an
overflowing variable.
The reason I bring it up again is that I have an important job due on
wednesday and I've been bitten by the same gremlin. If anyone has had a chance
to look at my previous upload I was wondering if you my have a suggestion for a
workaround. If you'd like me to upload my latest nightmare — let me know.
Ian.
>> opacity mapping fails
PMJI, but I've run across a few of the "gotchas". I haven't looked at your
sample, but try these…
1. Make certain in your 3ds.set file that you set "NEW-SUBTRACTIVE-TRANSPARENCY
= OFF". It may be ON as a default and not giving you 100% transparency.
2. Verify that your map has 0,0,0 at the transparent areas.
3. Try the same map in the shininess mapping slot to prevent any specular
highlights from appearing on the transparent areas.
David's suggestions are all excellent. The bottom line is that opacity
mapping works perfectly, but there are a lot of variables involved. Perhaps
Jonas can help you decipher what's going on with your specific file if you send
it to him. Jonas?
– G
Hmm… I never succeeded with my Absolut Decal using New Subtractive
Transparency = OFF. When I did, the bottle itself would lose it's correct
transparency.
I may u/l that project soon… but I was never truly satisfied with the
results. It was nice, but not professional.
Feel free to upload the project file to me. I'll let you know what you're
doing that's causing the problem if you do.
– G
Gary,
Apparently my first upload regarding my opacity problems went astray
before anyone had a chance to peruse it. After checking David Marks'
suggestions I discovered my current problem was indeed caused by
NEW-SUBTRACTIVE-TRANSPARENCY. Switching it off solved the problem. But why
doesn't it work with the new method? I think the new transparency looks better
— I could never get the saturation I wanted from the old. It always looked
too washed out. I guess because 3DS objects are just faces and not solid.
While I have your ear (eye?), the anti-aliasing of bump-mapped surfaces
doesn't seem to be as effective as that of the rest of the scene. I've tried
increasing the pixel size and softening the map in the material editor, but
without much effect. Any suggestions?
Ian.
Ian,
>> the anti-aliasing of bump-mapped surfaces doesn't seem to be as effective as
that of the rest of the scene…. Any suggestions? <<
PMJI, but I've found that the best way around this is to increase the
resolution and have nice smooth blend within the bump-map itself. Airbrush
tools in Photoshop/Photostyler etc, would do a nice job of this. You can then
turn down blur in the Materials Editor bump-map setup and still get the effect
you want. FWIW :)_
Thanks, I'll give it a try.
Ian.
The best way to introduce you to the subtlties of new-subtractive-transparency
would be for Phil Miller to upload the huge thread about it (that he's got
archived) from late last year.
Phil?
Re bump maps… Martin's response is pretty right on, in addition to stressing
that the bump map ought to use gradient bumps instead of harsh luma stepping.
Using a proper bump map with some map filtering will provide the highest
quality bump mapping you can achieve with any commercial 3D renderer this side
of Renderman.
– G