How to avoid HDRI from being visible in ground shadow/reflection ? (SOLVED)

hansolocambo · October 27, 2017, 12:22:51 PM

I'm sure it's a tricky thing to code, and there might be an option I missed in Keyshot. But my issue is : when I render an object in a Format that includes Alpha (Transparency), and with an HDRI environment as a background to get better lighting results, I end up with an image on a transparent background as expected, except the HDRI is slightly visible, in the ground shadow and/or in the reflection. I'd like to get the HDRI lighting used on the object, but not visible at all in the shadow/reflection. Is this a "bug" or is there any way to avoid that ?

Render finished in Keyshot's viewer :

Result :

Esben Oxholm · October 27, 2017, 12:34:23 PM

Hi!

I would change the background from environment to 'color' and go with 100% black.
That should solve your issue. I'm pretty sure that using the environment as background doesn't make a difference lighting vise compared to using a solid color.

Best,

hansolocambo · October 27, 2017, 12:51:53 PM

Using an HDRI environment DOES make an enormous difference in renderings dude.
It's lighting your object and makes it look totally different than a flat color. A 100% black background renders your objects 100% black. A red background makes them redish and so on. Your objects take the environment colors and it gives great and ultra fast results compared to lights (and speed is what I need right now). So yep, HDRI is a must.
And if I could feel its influence on the objects material but not on the ground shadows/reflection, it would be great

Esben Oxholm · October 27, 2017, 01:15:38 PM

Ha, yeah, I'm pretty aware that the HDRI environment as lighting has a huge impact. KeyShot is after all based on using HDRI's as the main light source. Think we're talking past each other here

What I was trying to say is that you can go to the environment tab and change the background from showing the environment to show a solid color, while keeping the HDRI as the light source. By using solid black you'll make sure that the shadows fades from black to complete transparent.

See attached:

mattjgerard · October 27, 2017, 01:34:51 PM

^^^This tripped me up substantially when I was first acquainting myself with keyshot. I will say though, that the color of the background you pick will show through your floor shadows, so pick white or black so you can blend easier. I made the mistake of rendering one out with a red background, was left over from just trying to do some edge work and needed the differential color to go against, but it bled through the floor shadows. Not a huge deal, just used the clown pass to make a mask and desaturated it.

HDRI does not equal background color, but can sneak in.

hansolocambo · October 27, 2017, 01:46:46 PM

I totally missed that. So simple, so logical. Indeed it'll fix the issue

Thanks Esben Oxholm

Esben Oxholm · October 28, 2017, 01:02:45 AM

No problem!

TGS808 · October 28, 2017, 08:59:04 AM

Quote from: Esben Oxholm on October 27, 2017, 01:15:38 PM
Ha, yeah, I'm pretty aware that the HDRI environment as lighting has a huge impact.

Boy oh boy Esben... that guy had no idea who he was talking to. Though it was nice of him to explain to you how HDRI and lighting environments work. Maybe now you can finally start producing some decent work with good lighting. LOL

Esben Oxholm · October 29, 2017, 09:10:42 AM

Quote from: TGS808 on October 28, 2017, 08:59:04 AM
Quote from: Esben Oxholm on October 27, 2017, 01:15:38 PM
Ha, yeah, I'm pretty aware that the HDRI environment as lighting has a huge impact.
Boy oh boy Esben... that guy had no idea who he was talking to. Though it was nice of him to explain to you how HDRI and lighting environments work. Maybe now you can finally start producing some decent work with good lighting. LOL

It is always nice with a little recap

I guess I wasn't clear enough in my first reply