Dirty blotches (coffee stains)in final renders

[majikstan]

Hello, I was wondering if any of you can give me an idea why this is happening and what is causing these strange stains on some of my renders.

I work for a commercial furniture manufacturer and I design the furniture in 3ds max.

Normally when I render something that does bring about these stains I tend to go into Photoshop and clean them up since I cannot work out what could be causing these.

Many times I have tested and examined with out any clue as to why mental ray creates them in the 2nd (final) pass of a render

this happens on some renders, not all.

My boss has alittle joke for them as being that someone left coffee stains on the furniture.

I have been haviing this problem for awhile now but I wish to finally find out why its doing this and adding these stains on the final pass.

I will submit soon some screenshots of some examples of this problem.

if any of you can give me an idea how to solve this what part is causing this the settings to ensure it does not create these let me know thankyou.

I shouldent have to go into photoshop just to clean up these dirty stains of blotches.

Sometimes it can be only one on the top sometimes it can be upto 3 varied sizes mostly in close proximity of the others etc.

[Justin Hunt]

these blotches are caused by the "Number of interpolation samples" setting for Final Gather. If these are stills then switch to the Sample radius methode. (the old way of doing it). the bloches will clean up

 

However this wont be any use for animations

 

JHV

[majikstan]

Thanks for replying so quickly.

This method worked very well, thanks for that as most of my renderings are just that screenshots, its solved most of of my renders from now on, I just rerendered a couple of components again and yes they are now nice and clean (no dirt or stains etc ).

 

However as you said that for animations it won't work, then I still do wish to know sometime how to correct that such as the mysteriouse smoke effect that seems to develope on a selection of frames.

Since the stills problem was to do with the fg's, default 27 then is the smoky effect caused by this.

would raising or lowing the fg remove that smoke effect.

I had a wall unit I did the other day with a flip down door.

animated first frame no stains nor the last frame, however the smoke effect seemed to begin around frame 15 and began to disapear again close to frame 50.

the animation has the flipper door opening down and the lower two doors swinging open, the smoky blotchy effect shows up around the front of the flipper door above the two other doors.

Let me know what to do about this thanks.

I canceled that animation from rendering at frame 23 and only renderdd screenshots for fame 1 and frame 100, cleaned up frame 50 in photoshop, etc.