KeyShot Forum

Technical discussions => Materials => Topic started by: Georg Malm on May 22, 2011, 09:08:35 am

Title: Artifacts on transparent materials
Post by: Georg Malm on May 22, 2011, 09:08:35 am
Hi!
Do somebody know how to avoid those strange artifacts on transparent materials when they overlaps other transparent or opaque materials?
Title: Re: Artifacts on transparent materials
Post by: justindustrial on May 23, 2011, 03:24:04 am
What you're seeing here is coincident surfaces, basically surfaces that occupy the same space. This creates 'triangles' throughout your rendering. Since two surfaces cannot physically occupy the same space, the best way to fix this problem is to create a gap between your parts. I personally use 0.5mm which is pretty generous, and leaves a bit of a shadow gap. If you want 0 visible gap, try overlapping the parts slightly so they actually intersect in your model. This might create problems on your 'A' surfaces where you'll have a strip of coincident material so you might have to create an offset here. Sorry for the wordy description but I hope that helps. If you look back through the forum there may be some images on how to resolve this issue.
Title: Re: Artifacts on transparent materials
Post by: Speedster on May 23, 2011, 09:59:01 am
Yep, you absolutely have to have a tiny gap between one or two transparent surfaces.  Also, as Jeff showed us on the webinar, set your gamma on the Realtime Tab to 2.2!  This is really the trick, but you may have to notch back to like 1.8 or so.  I just rendered a vacuum formed packaging tray for a medical device, also with many transparent components. It has three transparent parts (tray, insert and cover), and it would have been impossible without the 2.2 gamma setting. Plus, I kicked ray bounces to 16.  Of course to have to adjust some other stuff to compensate, but that's no biggie.  I can't show the tray at this time, but I'll try to pull a small area that I can share.
Bill G
Title: Re: Artifacts on transparent materials
Post by: guest84672 on May 23, 2011, 05:27:02 pm
in realtime, make sure to check detailed indirect illumination in the realtime tab.
Title: Re: Artifacts on transparent materials
Post by: stdam on November 23, 2011, 09:48:38 am
how did you make the mat transparent?
Title: Re: Artifacts on transparent materials
Post by: PhilippeV8 on November 24, 2011, 03:33:42 am
Been there, done that ;)

Keep 0.1 or 0.05mm between all parts .. for sure if one is supposed to be glass or something transparent is the trick for this one indeed.