Shadow Catcher perfect/universal shadow

[raistlin]

Hello
I've try to be as clear as possible, i need to separate a subject (for example a car) from the background and compose that in photoshop.
Myy customer want to have the car AND her shadow on a layer, and the background on another.
So..
Of course i think about Shadow Catcher, but..
It seems to be a little bit complicated to have a perfect match..

I've place a plane under my car, with a shadow catcher to keep the shadow but i've a wrong shadow..
Too dark or too grey (my BG is a Cyclo like a photograph studio) and of course.. it's white and roughy...

Can i hope a perfect result, to place my car with her shadow on any background? or we have to fake it ?

Cheers !

[romullus]

Hi,

If you want shadowcatcher in comp to look exactly the same as in VFB, then you need to save the image in linear format and perform composition in linear color space.

[raistlin]

Ok, so if i can understand, when you say "in linear mode" i've to understand "without post effect compositing or lut, just a raw render" ?

If it is, ok, but my problem is a little bit more than that, the shadow i've is too strong OR too... impossible to compose (when yuou make it 0.1 value, for example, we get a shadow "washed" and white, impossible to compose..

I've read some post where people render invisible object and ujst it's shadow on a shadow catcher... so
I'll try it, but i thing the shadow intensity proble will be present too..

thx in all, i'll take a look later, and i came back (the newt week or in the week end.

[romullus]

Ok, so if i can understand, when you say "in linear mode" i've to understand "without post effect compositing or lut, just a raw render" ?

Yes, you need to save the render without any tone-mapping and post-effects. Also you need to save it to 16 or 32 bit linear, i.e. without gamma correction. If you will do composition in photoshop, make sure to work in 32 bit mode and use add blend mode for background.

If it is, ok, but my problem is a little bit more than that, the shadow i've is too strong OR too... impossible to compose (when yuou make it 0.1 value, for example, we get a shadow "washed" and white, impossible to compose..

I've read some post where people render invisible object and ujst it's shadow on a shadow catcher... so
I'll try it, but i thing the shadow intensity proble will be present too..

thx in all, i'll take a look later, and i came back (the newt week or in the week end.

I think it would help if you could show some examples of what you're getting, or what you want to achieve.

[raistlin]

Yes, i'll do it in a few days, i'm on deadline and i've sleep since yesterday, but thx for your kind help.
You're really cool

[Aram Avetisyan]

Hi,

If you were render the same car on a white background, in reality (or in 3d scene, a real render, not composed one), then the shadow would be different than if you had a black background.
So the shadow will vary in reality.

But if you want (meaning that is the case) a static, somewhat mid-grey shadow with somewhat medium opacity, then I think even simple png would do the trick.
ShadowCatcher's shadow amount with the other options actually give you good enough control over the shadows.

You can as well render out the shadows render elements and use it separately for more post control.

As Romullus mentioned, showing some examples or use case will make it more understandable to suggest you the best.