vray dome light - IBL

[FlytE]

Right... ive looked around at what everyone has to say about the dome light but Im still having problems with it.... am I missing something?

 

I have a high resolution hdr used in the dome, and basic but decent render settings - only a few increases in number of samples, med prest on irmap, qmc secondary, exponential color mapping etc. The problem I have is that the dome light comes out extremely dark. On the previous hdri it was practically black until I increase the hdri's multiplier to the highest possible setting (1,000,000) or something, and the result was poor quality. I then used a better res hdri and this helped, but I still need to increase the mulitplier to like 1000, then it just burns out and casts white light.

 

Something doesnt seem to be adding up..... surely I shouldnt have to have rediculous multipliers and really high res hdri's to get some low quality IBL ?

[Stephen Thomas]

When you say low quality, are you talking about the sharpness of the shadows? If so this has less to do with the resolution (6000px e.g.) and more to do with the dynamic range of the hdr. There is a huge variation in commercial hdri's regarding the actual dynamic range of the image. In some the brightest part of the image is only 3 or 4 times greater than pure white (1.0 float). Others may go into the hundreds or even thousands.

 

Compare this with using a direct light which has not much more intensity than your skylight. The best hdri's for crisp shadows would have very intense small points of light. Try the free downloads on Paul Debevec's site, some of which have a dynamic range of 200,000:1 and see if this makes a difference.

 

http://www.debevec.org/Probes/

 

For truly good results though, I still feel there is no match for a good hdr / direct light combination.

 

Good luck!

[BrianKitts]

How about an image of what you're dealing with?

 

I never use the dome light for my HDR's I always assign a vrayHDRI in the environment override rollout, and then stick in in the background channel unless I want to use something else. Point being, I never have a problem with the lighting from it even with low res hdrs..... is there an advantage to the dome light that you are trying to make it work?

[Stephen Thomas]

How about an image of what you're dealing with?

 

I never use the dome light for my HDR's I always assign a vrayHDRI in the environment override rollout, and then stick in in the background channel unless I want to use something else. Point being, I never have a problem with the lighting from it even with low res hdrs..... is there an advantage to the dome light that you are trying to make it work?

One difference is that the dome light actually shoots photons meaning that you can use IBL to create caustic effects. Also the dome light tends to give better definition to the shadows, though the render times tend to be greater after dealing with noise issues.

 

The following images are just a quick test, all images rendered with the same settings. On the very high dynamic range image placed in the environment slot things seem to get very strange.

[Nic H]

nice tests, picture says a thousand words!

[Eric Sosa]

hum, I never use skylight enviroment ligth, neither vraydome.

 

ligthning outdoors, is always with vray sun. interioirs with vray sun, vray planes and standard spots with vray shadows.

 

HDR's is mainly with the reflection/reflaction enviroment overrride rollout or applied in the mat enviroment slot.

 

...when do you realy deal with the skyligth enviroment shadows?...tho it looks like a cool choise the use of the vray dome of those pics.

[Three D]

hdrlabs dot com

 

I bought the HDRI Handbook some time ago and it is definitely worth a read for anybody interested in IBL. The section on IBL in CGI is relatively small but the CD that comes with the book contains some excellent scripts and tools for creating and using IBL along with some nice HDRI files, although a lot of the CD resources can be downloaded fron the HDRLABS site.

 

The hdrlabs dot com forum is also an excellent resource. Have a look.

[mahorela]

I use the dome light regularly as I find that alot of HDRI's tend to get splotchy when put through the vray environment override. The multiplier on the light means nothing when you have a HDRI loaded into it.......it actually just casts a secondary skylight type effect which is not very nice......it does however have to have some value or it will not cast light provided by the HDRI and will default back to the vray environment override or the standard max environment????

 

I put the multiplier down to .01 and then I adjust the HDRI multiplier and the gamma in the material editor if I want more light.

 

You should also check off effect relections on the dome as well.....if you don't, glass etc will come across a little flat.