Sky and HDR background

[mjerome]

Hey guys,

Although the results from lighting via HDR in the sky slot is pretty good, it doesn't produce shadows. I change the map in the sky slot from bitmap (the HDR) to Sky, and keep the HDR bitmap in the background slot. I do get the shadows, but the sky disappears and is replaced with predominant black (I used to think it was blacked out completely, but at an angle I was able to see some of the clouds).

Is there a way to strike a balance between the Sun/sky while keeping the HDR background?

Thanks!

Mark

[Jackson_cg]

Re: Sky and HDR background

Forget about the background slot, that has nothing to do with GI lighting.

To combine HDRI lighting (LDRI jpgs and pngs also work BTW) with VRay Sky you have to use them as Blend material in the GI slot. Put the VRay Sky in slot A, HDRI or LDRI in slot B and a blend ratio of between 0.99 and 0.999999 (this is because the VRaySky is extremely bright compared to bitmaps.) Adjust the multiplier to suit. You'll get nice sun shadows, but with the subtle realism of image-based GI lighting.

[mjerome]

Re: Sky and HDR background

Jackson,

Thanks for the reply. But what I'm aiming to do is get the shadows cast by sun/sky (which HDRI lighting doesn't give too well) combined with the graphic background of the HDRI image, because the sun/sky alone renders the background black.

Any tips?

[Jackson_cg]

Re: Sky and HDR background

Increase the background multiplier. If you're using the current VfSU version you'll need a multiplier somewhere between 1 and 100, if you're using an older version you may need to push it up into the thousands or even millions to make it visible (many factors affect this parameter). You'll need to do trial and error to find a balance between the background being bright enough without suffering burn in bright areas.

[mjerome]

Re: Sky and HDR background

Thanks Jackson!

I tried 1M for the multiplier, now the background's white. Knocking it down to a thousand aces it! I'll just see if there are any parts adversely affected in the image before I stick to the thousand.

[nomeradona_cg]

Re: Sky and HDR background

Forget about the background slot, that has nothing to do with GI lighting.

To combine HDRI lighting (LDRI jpgs and pngs also work BTW) with VRay Sky you have to use them as Blend material in the GI slot. Put the VRay Sky in slot A, HDRI or LDRI in slot B and a blend ratio of between 0.99 and 0.999999 (this is because the VRaySky is extremely bright compared to bitmaps.) Adjust the multiplier to suit. You'll get nice sun shadows, but with the subtle realism of image-based GI lighting.

what an insight jackson... thanks.

[fpedrogo]

Re: Sky and HDR background

The only mapping type that produce light on the background slot is Sky. Is weird, but produce light. So maybe you don't have to use blend mapping at all. Try just put the HDRI on the GI and the Sky on the background in this way you can adjust separately the multiplier or the intensity for the HDRI and the SUN. If you want something different on the reflection you can still override the reflection and the refraction on the Environment rollout.

Best