Dumb saved light map question

[AJLynn]

I'm trying out PPT using the Sponza Atrium model and found a big gap in my knowledge that I'm not seeing an answer for. When I save a .vrlmap file using a light cache that I made with, say, a view from the floor in the middle of the atrium, how well does that work when I go to other views? Do I have the lighting solution for the whole model like in Lightscape or if I go to the second floor am I losing accuracy if I don't do a new solution?

[lambros]

You can check the vray tutorials on rendering from several views. The best way to handle this is to render from different views using irradiance maps using the "add to current map" function and then save the map. This way you will have it all covered. You can even load the map in the irradiance map viewer and check if some parts of your model need another render.

Light maps cannot do that. I think that light maps, as well as irradiance maps are view dependent, so no much luck there.

[Christopher Nichols]

When doing the PPT, there is no saving anything. It is like Maxwell, you have to wait for every render. I think you are confusing PPT and Light Cache.

 

For light cache, it is vew dependent, so if you change views you will need to render it again and save the data again.

 

But the light cache can save the samples along a camera path. So you are not tied to one view.

 

Walk your way through the interiors tutorial Vlado did. It will show you how to do a lightcache sample along a camera path.

 

http://www.spot3d.com/vray/help/VRayHelp150beta/tutorials_imap2.htm#part1

[AJLynn]

Wait a minute... I thought I did save a PPT map - did the usual setup with primary and secondary set to light cache and light cache set to PPT, 2000 subdivs, let it finish then hit save to file. It saved a map file then I put light cache in From File mode, doubled the resolution and did a render that ended up being okay but not great.

 

Edit: I went and re-read the Spot3d PPT tutorial and they say "In addition, the light cache from a path traced image can be saved and re-used later on for a normal rendering." Shouldn't you be able to use PPT until the lighting is "good enough" but still noisy then use the map in a final render to get to a nice clean image? Kind of a compromise solution?

[AJLynn]

Update: it works. Didn't come out perfect, but I do like the effect and it wasn't too slow.

[Christopher Nichols]

The problem is that PPT does eveything (AA, caustics, reflection, GI, etc...). Basically the whole image. The only thing that can really be saved is the diffuse GI.

[AJLynn]

Naruhodo. This makes much more sense now.