Lights and Render Time

[LookOut]

I want to render views from two seperate rooms in my model. Does Vray calculate the lights affecting the current view only? If I place lights in each of these rooms, are the render times affected by the total number of lights in the model?

It seems a hassle to have to go through and turn off lights if they're not in use but I want this to be efficient and faster.

[andybot_cg]

Re: Lights and Render Time

a quick way to turn on or off a set of lights would be to put them on separate layers that you can turn off when they are not in view. (I agree it is really a pain to edit each light.)

-Andy

[thomthom]

Re: Lights and Render Time

Don't know about the lights thing - but in general, to optimize a scene remove everything that doesn't affect it.

I often have a model per view when I render larger complex models. I make a main model, which I make a copy of for the given scene I need and populate and detail. Yes it's extra hassle with extra files - but if you need performance that's what you need to do. Cut, slash, erase bash.

[ACastro]

Re: Lights and Render Time

Hi,

Yes I think what Andy said the results (the same for all objects and materials that are not needed for the scene ).

to aggravate the problem, the unique possible solution at the moment for that "VrayLumen" gives me one error and does not work with me

unfortunately I do not know why, gives me this error msg:
is not possible to find
....:/program%20files%20(x86)/goggle/google%20sketchup%207/plugins/VRayLumen//htm...
make sure that the path or internet address is correct.

is it because of my version of Sketchup??? ???

Cptos.

Castro

[andybot_cg]

Re: Lights and Render Time

Thomas -
I'm curious - is there a difference in parsing/ render time between the two methods 1. keeping all model info in file but on separate layers, or 2. having separate models of spaces?
(The only limits I've found of keeping everything in one model with separate layer groupings is that SU starts to get slow with larger complex files. The other limit has been too many materials - since it seems Vray has to parse them out to load the file - whether hidden layers are on or not.) I've found turning layers off has kept render times manageable for me. Maybe I'll do a test on a large model and see if I can discern a difference.

Andy

[thomthom]

Re: Lights and Render Time

Good question. I have a suspicion that VfSU process hidden entities. (Though I'm not sure about this. I've wanted to do some tests on this.)

[andybot_cg]

Re: Lights and Render Time

Okay - so I did quick test. I took a model with 140k faces. I made a hidden layer with 30k faces in it with all the objects that were not in view. I did one render with the layer turned off, and another with the layer (and all contents) deleted. Both clocked in at almost identical times, one was 15m 26.6s, the other was 15m 21.8s. The rendering settings were LightCache and DMC, so I don't know how much variability there is from one render to another. Also - Vray 1.48.89, and SU7.1
Just to round it out, I did a rendering with the layer turned on, and I got a time of 32m 54.1s Definitely a good reason to turn off/ delete everything not visible in the rendering!

Andy

[thomthom]

Re: Lights and Render Time

I'd expect the render time to be similar. But I'm wondering how it affects the processing time.
You get some time stats if you keep the Ruby Console open before you click Render - but there is an un-timed lag after it says it was made the XML files and the render begins. One would need a stopwatch to time that.

[andybot_cg]

Re: Lights and Render Time

I did a quick check - they all took about the same time to process (I used a stopwatch on my computer to time from pushing render button to when the buffer window showed up - so not perfectly exact):
Layer turned off: 53s
Layer deleted: 51s
Layer on: 63s

[thomthom]

Re: Lights and Render Time

Intresting.

[andybot_cg]

question for Fernando or Devin - how does vfsu deal with processing layers that are off, etc. AFAIK, vray ignores anything that is hidden, which is why animation that relies on hidden layers does not work since vray doesn't load anything other than what it sees.

[dkendig]

We do iterate over all entities in the scene, regardless of visibility, so that we can test to see if an entity is visible. It doesn't take long to test to see if an entity is visible, but it does take a little bit of time. If it is determined that an entity is not visible, we do not go through the process of writing and reading a chunk of xml for that entity, which is where the real time saving comes in to play. We do not re-examine the entities in the scene during an animation to determine if the visibility has changed.

[ValeroStudio]

I would much rather wait a few more seconds for the file to parse than have 4 SU files. You know that a client is going to make a change and then you have 4 files to update. Pay 10 seconds and save a hour down the road.