But isn't that exactly what HDRI is good for? Reflected light coming from all directions to all parts of the illuminated object. Also to places which are turned away from the light source. Exactly what a large number of bounces does. Only more effective, faster.

As far as I know, the basic idea was: shoot the surrounding room of a scene once in HDR and then shoot the objects in an empty room with an HDRI (High Dynamic Range Image) as "light source".

This way, only the actual object has to be rendered, not the surrounding area. And you can take the shots anywhere. You don't have to be at the place where the scene actually takes place (a modified technique is also used today in film productions: with LED screens as a light source around the object to be photographed).

About your image above: The render time for an equivalent shot using an HDRI as the light source should be a fraction on the same hardware. To get exactly the same result, however, you would need an HDR image of the same room you used when rendering with Bouces.

Complicating matters, however, is the problem that the Cyles implementation in Poser 11/12 doesn't handle HDRIs well. They quickly create fireflies depending on the image. Depending on the HDR material, you may not be able to get rid of them. No matter how many bounces you render with.

This is completely different in Blender. There it works perfectly and many times faster than in P11 and P12. So fast, in fact, that Cycles can be used as a full-fledged preview even with relatively low graphics card performance - just in those cases when Eevee isn't enough.

Rendering with many bounces instead of HDRIs is probably only good for Poser 11 and 12 (we will see how it is in P13). It should not be taken as a general recommendation!

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