Having some difficulties understanding the environment light in H11 – everything works fine but I’m not sure if I really understood how the different render modes actually work (especially with env – maps). So, why does AO deliver darker results than direct lightening? Is it because direct lightning also takes the camera position into account (recursive ray tracing) meaning secular light is also calculated? (How many shadow rays are sent to the environment hemisphere? – are these rays evenly contributed over the hemisphere?) - What’s the difference between direct lightening and ray tracing background? And last but not least what is the relation between the render modes set in the env-light and the render mode set in the Mantra ROP. I guess these are many questions but it would be great if someone could give me some advice on how these things work. Thanks in advance.

have you seen this?
http://www.sidefx.com/docs/houdini11.0/nodes/obj/envlight [sidefx.com]

Beyond docs, if you're still interested what is going on under the hood (as merging different render modes into a single light involve some logic), you could take a look in $HH/soho/python2.x/wranglers for: HoudiniEnvLightIFD.py and HoudiniIndirectLightIFD.py and compare these with v_gilight light shader (Global Illumin. Light).

You will notice how those three things are silently changing settings depending on a number of parameter, including render engine.

First of all thanks for your answers -I already red the description of the env-light but didn’t clearly understand how these different render modes affect the final look of the Render. AO produces darker results than direct lightening – is this because mantra sends out more samples toward bright areas of the env map? And ray tracing background produces even darker results – but doesn’t it work similar to direct lightening?

@ SYmek : thanks for the tip , but this seems to be too advanced for me since I’m new to Houdini and never really worked with python before - I maybe should keep this question till I’m more experienced in Houdini.