Interior - light through glass blotchy

#1

Can anyone help. I’m practising to try and create some interior renders and have a simple scene with one window and a mr daylight system set up for the lighting. I’ve used the standard mental ray preset materials for glass, initially frosted glass but also tried (physical) and (solid). The light shining on the interior appears to blotchy no matter which glass type I tried. Does anyone know which setting I need to change and where I should start looking to try fix this? I’ve used High Final Gather settings, 3Ds Max 2009

#2

Does it look the same with the glass turned off ?

Regards,
Mike

#3

No, it doesn’t. With the glass switched off the blotchiness is gone. Initially I thought it was because the glass had a ‘frosty’ preset but the results are the same even with clear glass

#4

break the glass out into it’s own render layer. With the image you’ve given, I can’t even tell that there is glass there…

#5

You could set the glass to not recieve or generate FG. Then you wont need a seperate render layer.

Regards,
Mike

#6

Looks to me like you may have some GI photon leaks (wall corner, floor/wall joint/etc). That can cause problems with your FG solution. Can you confirm whether or not you’re using GI + FG or just FG alone. If GI + FG then you’ll want to disable FG and balance the GI prior to enabling FG in order to get a smooth end result without leaks.

#7

Yeah, i noticed those leaks too and was going to have another look at it tonight and check everything intersected ok. I am using FG and GI. Could these leaks be causing the blotchy problem? Will do as you suggested and disable FG for now

#8

Ok, I apologise if this is a stupid question but having rendered disabling FG this is the result. What setting do I need to be concentrating on to smooth the result. I’ve tried increasing average GI photons per light which gives the 2nd result but not sure if there’s something else I should be looking at?

#9

Sorry for the slow reply. My reply started to become long winded, so I figured I’d go ahead and just make a blog post with some tips for interior rendering with mental ray in 3ds Max. Link: http://jeffpatton.net/2011/11/mental-ray-physical-sky-tips-for-architectural-interiors/

#10

Cheers loads for this, I did manage to figure out I was missing an mr Skyportal at the window, but seems there’s plenty of other things i’ve missed too, so now going to go back and start from the beginning reading through your blog.

Thank you tons for your time with this

James

#11

Cool, no problem. Glad to hear you figured out the main problem.

#12

Sorry to return to this old thread but I was just wondering if there was any particular method for creating Ambient occlusion passes for interior scenes like this with camera faicing a window with light streaming through it. The reason I ask is because I have tried to create an AO for this scene but on the area around the window loses it’s ‘bright sunlight’ directly on the inside of the window due to the ambient occlusion in this area, i hope this makes sense

#13

just render out a rgb matte for the light. Just apply a 100% white lambert and convert your FG to red (or any primary color). Also, reduce the bounces so you can only isolate the window area (otherwise it’ll flood the room with red). And turn off all your other lights (if you are using any)

For those who trust the mentral ray render passes, you can also break it out that way.

#14

You only wanted to multiply your fill light by the ambient occlusion pass. Ambient occlusion mimics shadowing, since your sunlight already has shadows, it does not need additional shadowing from the occlusion.

#15

I have to agree with Kanooshka, but the items on the floor at the bottom seem to not be well grounded (which AO will take care of)

#16

Cheers for your replies, yeah it’s the items under the window I want to try and ground more so might see if I can break the AO to only be used under the window to try eliminate my problem

Thanks
james

#17

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