[jrm1]

I've looked at the documentation on the subject and I can't seem to discover how to get started. It describes the concept and all the settings but I couldn't see anything about first steps. What to look for in buying HDRs and also where to put them in your 3D model. Do you place them on a sphere inside the model or in Studio? How do you align it so the sun or bright part of the sky is aligned to north for the location. etc.

Any help gratefully accepted. Many thanks.

[choo-chee]

to start with, use high-rez images.
you don't have to apply it to a sphere - the render settings has a place to activate HDR and control of all 4 channels (I use maya, it's in the render globals, after the sky/sun options).
you can control the orientation of it there, also.

[jrm1]

Thanks choo-chee. What dimensions minimum would qualify as high res? Any brands/companies you can recommend for skies?

[Hervé]

http://www.hdri-locations.com/

[Primus]

http:/hdri4u.com
https://www.moofe.com/