why hemi+hdri change look to the texture?

[marko70]

why this happenn?
1 only hemi lamp http://www.flickr.com/photos/64493973@N06/9154165136/
2 hemi+ hdri texture http://www.flickr.com/photos/64493973@N ... /lightbox/
As you can see in the second image the nut look completly different the only change except the risolution is the texture hdr under hemi lamp

[bdancer]

Re: why hemi+hdri change look to the texture?

Because VRayDomeLIght (Hemi) is a smth like virtual sphere around the scene and when using hrdi it works like an emit texture, so bright areas of hdri produce brighter direct light.

[marko70]

Re: why hemi+hdri change look to the texture?

ANd ther is no way to fix that?

[bdancer]

Re: why hemi+hdri change look to the texture?

It's a feature, this is how it's designed to work =)
Why do you need to add a texture then?

[marko70]

Re: why hemi+hdri change look to the texture?

Because if tought that was the way to use hdr image to illuminate a scene but th aspect of texture of the nut
Change also if i use a texture i world as you cqn see in the second link of flickr i stiil have problem with hdr using as
Background image because appear very shining areas

[bdancer]

Re: why hemi+hdri change look to the texture?

Basically there are 2 way to use HDRI:
1. IBL (Image Base Lighting) and you were doing everything right, you should use Hemi light (which will be translated to VRayDomeLight) and use HDRI in lamp texture slots.
2. Use HDRI as World texture in Background or GI slots.

The main difference is that IBL will produce direct light and thus could be used without GI enabled. The second approach will produce only indirect light and you must enable GI to see its working.

Background image because appear very shining areas

This is how it works, HDRI has much wider dynamic range (so colors are not from 0.0-1.0, but could be 0.0-100.0 or more for example). You could try using physical camera and color mapping setting to control overall brightness.
Also check "Affect Background" option in Color Mapping and Clamp feature.

[marko70]

Re: why hemi+hdri change look to the texture?

But why,using hdri the morph of my nut change?,i try to illuminate another scene and using or no the texture in hdri seems affect the reflection and the wood appear more and more glossy,anyway i'll post at soon another pics and file.
Thank you

[bdancer]

Re: why hemi+hdri change look to the texture?

Sry, I don't get about "morph"... What was changed is lightning conditions. Without texture light goes from every direction meaning no shadows. With texture, bright parts produce more light and you see shadows, that's why you see more bump and stuff.