dome light, no sharp shadows

[gjwegner]

hello,

 

I am using an HDR from Dosch's Extreme Hires selection in a VRaylight(dome) and can't seem to get any sharp shadows. In fact, I see no difference between the dome results and the environment override when using the same HDR. Any thoughts?

[Ricardo Eloy]

Well, normally the dome light looks way better than the simple environment. Maybe you are not seeing much difference due to:

- low subdivs?

- wrong hdri map setup?

- the map doesn't cast any sharp shadows?

Check these and tell us what happens.

[Claudio Branch]

 

Can I find a free hdr, perhaps a sample somehwere, that should produce sharp shadows?

 

 

I don't believe that you will be able to get any sharp shadows out of an HDR. I use the same Dosch library with a V-Ray dome light oriented to correspond with the suns' position in the HDR. It works...

[Stephen Thomas]

It is possible to achieve reasonably sharp shadows with an HDR, but this is entirely dependant on the nature of the lighting situation and dynamic range captured in the image itself.

 

These threads may help:

http://www.cgarchitect.com/vb/25080-vray-dome-light-ibl.html

http://www.cgarchitect.com/vb/21927-vray-hdri-dilemma.html

[gjwegner]

thank you all for your responses,

 

Supplementing the HDR with direct light has always worked fine for me, however, after seeing the results from the dome light I was compelled to try it out. It seems that I just need some HDR's with a higher dynamic range, even though it was recommended in a previous thread that this set of HDR's by Dosch would created the sharp dome light shadows.

[Stephen Thomas]

After looking at this issue a lot my conclusion is that while it is possible to achieve, it is just not necessary. My advice is find some pretty HDRs that you like and which suit the kind of scenes you will be creating and go for those. If they are high enough resolution that they can double as background images then even better, as your lighting and background will match perfectly.

 

I can get amazing crisp shadows from some of Paul Debevec's light probes for example, but when will I ever need to use the lighting from inside a cathedral in an architectural project?

 

Using the HDR in conjunction with a direct light source will give you the most control over your scene. Try and view the use of HDRs as giving your image a certain colour or mood, rather than a magic one-button lighting solution.

 

Also most HDRs lack the sort of dynamic range that causes problems when using the environment slot, so this method is still perfectly valid. If a particular file is causing problems, or you want to create caustics from your HDR then switch to the vray dome light.

 

Just my thoughts..