VRAY for SU HDRI lighting

[ntavian]

hello all,
hopefully somebody here can help me on this one.
I am having trouble with VRAY for SU using HDRI files in both the GI (skylight) and the Reflection/refraction (background) slots
I seem to be getting these weird lighting artifacts
anyone have an idea on what is causing them?
switching HDRI files doesn't seem to help,

WHY CANT I UPLOAD AN EXAMPLE PICTURE?

I cant seem to find where to upload a picture

[fpedrogo]

Hi
If you use an HDRI in the GI(Skylight) you are basically using GI light. Meaning that you will sampling the light using the GI solution. I'm guessing that you are using IrrMap and LC. So, there are three option that you can do in this case.
1. Increase the GI solution setting very high until you don't get splotches. This is not the best solution, because your rendering time will drastically increase.
2. You can open the HDRI in photoshop and reduce the size to 512x256 and also add a Gaussian blurry effect, until you smooth (remove all the details) the whole HDRI. This will avoid V-Ray to sampler all the details on the HDRI and just focus on the areas that produce the light. This is better than the option #1, but it will not produce nice shadows and a lack of contrast.
3. Use a dome light. This is the best solution. It will produce sharp shadows, better contrast, better caustics, fleakering free animation, etc. The reason is because V-Ray use important sampling to produce direct light from the brighter spot in the HDRI. It is not GI light. Some users think that the dome light is slow, but if you want to get the same result that you get with dome light, using the option 1 or 2, you will have to increase the GI so high that the render time will be longer than the dome light.
So, for the best render result use option 3. For the faster rendering time use option 2.

[jadeoasis]

hi guys,

i was just starting write new thread when i say your posts.

any idea how to import a new hdri into sketchup components ( a part of the vray express)



does anyone seen IES lights as components too?

by the way, you´ve got an excellent idea, to reduce size of hdri and blurry in PS!