View Full Version : occlusion/dirt map

12 December 2006, 01:41 AM
I am trying to get the workflow for compositing with ambient occlusion.
I am using max 9 with vray .
how to work best in terms of saving render time, how should I render it? shoul I render the ambient occ with gI aswell??

Ian Jones
12 December 2006, 03:31 AM
I would probably suggest keeping GI and AOCC seperate because AOCC can be used as you mentioned as a dirtmap and for interesting compositing effects. Also if you change your lighting and need to recalculate GI why recalculate AOCC aswell? Keep them seperate IMO.

12 December 2006, 12:20 PM
I agree keeping the AO separete from the GI. typically I put the vraydirt map in the selfilluminating slot and render it out then I comp it using multiply over the original rendering. Lets me keep the rendring quality fairly low and the AO pass brings in the details I need for the image

12 December 2006, 06:30 AM
sorry but I still have some question:
I render the final image using GI and IR . then I overide the material with dirtmap. then I render it again with GI and IR. Is this correct ?? or supposed the Aocc doesn't need to render with Gi or light maybe ( saving time) ??
I tend to render without pass: diffuse, shdow ,spec, because it takes more time.
the deadline for a TVC in my country is extremely fast. plus the online in my company was bad. they not retouching it .. only compilie it :D

can u share ur workflow?? any good tutorial or reference...?? hows the pipline in ur company??

12 December 2006, 09:21 AM
Well I don't have any good tutorials but I turn off the GI (you don't need any light either cause the material is selfilluminating) when I render my dirtpass and use the material in the material overide. If you have GI on it will slow things down plus it actually counteracts what you are trying to achive because the light will wash out the fine details you recieve from the dirtpass. Mind that using a straight dirtpass will not be correct cause it dosen't take into account the bouncelight. If you want that you should use detail enhancement in the irradiance map. This will slow down rendering alot though so I stick with a pure dirtpass and adjust the multiply level in the comp till I get a result i'm happy with.

ps. Be sure to have the diffuse set to pure white in the dirtpass material so the onuccluded parts won't add anything in the comp .ds

12 December 2006, 09:34 PM
thanks alot. it really helps. I want to upload some pictures to show some of the step that I did. where can I upload images besides photo bucket, it ussualy scale down the size of the image when it almost full. ??

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12 December 2006, 09:34 PM
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