Matte shadow limitation or bug??

[HSR]

Hi
I have a problem with the matte shadow in cinema4d. It's the same problem as in this thread, but no solution found..: viewtopic.php?f=30&t=45959&p=231197&hil ... er#p231197

The matte shadow works great for one lightsource only, as far as I can tell. From what I can see, shadows from all lightsources are rendered fully visible when you use the matte-option. To illustrate what I mean, have a look at the pictures.

1 pic.
scene is lit by an HDR image.

2. pic
matte shadow is enabled. You get the shadow as expected

3. pic
A fill light is added in the scene.

4. pic
matte shadow is enabled, but now you get a really dark shadow from the fill light.

Is there a solution to this?

Thanks

[bepeg4d]

Hi.
the matte option was a solution for offering fast shadow catcher, but it has some limitation as you can see.
The new Render Layer system is the correct solution now, have you already tried it?
http://inlifethrill.com/trainings/octan ... rendering/
ciao beppe

[HSR]

Thansk for your reply.

I assume you are talking about "Multi-Pass Rendering / Part 3 - Render Layer" - about 7.50 min in?

I tried this, but it gives me the same result. The shadow from the fill-light is waaay too dark. It should not even be visible. And it does not matter what power your lightsource is. It can be 0,0001 or 2000. Strenght of the shadow is the same.
Notice in the tutorial - there is also just the lighting and shadow from an environment. There are no lights in the scene... I guess thats why it works...

See attached...

Any suggestions to deal with this?

Thanks anyway

[bepeg4d]

Yes correct, the shadow pass is not related with the light power, it's the same for the sun light, if you reduce the sun power, the shadow does not change in intensity.
You don't need a fill light If you need less dense shadow, you could reduce the amount of the layer in your compositing app. But, if the fill light is needed in any case, you can reduce the angle in order to spread the shadow:

ciao beppe

[HSR]

It's a shame there is no solution to this.
I hope this is something that can be worked out in future versions. Having multiple lightsources in a project is a must have in many situations, and the ability to get the shadows on a transparent background is a wonderful thing. But since the shadows all comes out a 100% from each light, this pass becomes pretty useless in compositing.

Im working on a project now, where I have an object standing on a floor. I need fill-lights in my scene to achieve the look im going for. In compositing I need it to be on a completely clean background with just the shadows. I don't know how to achieve this with octane without doing 2 renders: 1) turn off all lights except the light casting the main shadow and render. 2) turn on all lights and render the beauty pass with alpha.

Is there really not a better way to do this with octane?

Thanks anyway

[bepeg4d]

Hi,
a solution for fill light shadow is to activate the "Surface brightness" option in order to have the same illumination with any dimension, and then enlarge the emission in order to blur the shadow.
Here is an example with emission 100x100 cm:

and here with 1000x1000cm:

ciao beppe

[HSR]

Hi
Thank you for your reply.
For some reason I do not have the "surface brightness" option in my light tag??
While your solution might work for blurring out the shadow, it is hardly a solution for the lighting.. By altering the size of the light, you are also altering how this light is affecting the lighting of your object.
All I want is have a fill light in my scene, to add some extra lighting to my object, but I do not want a dark shadow cast from this fill light when using the shadowcatcher. I understand this is probably a limitation in octane at this point, but down the line, it would be great if there was a way to update the shadowcatcher to be able to take ligting of shadows into account - or at the very least be able to exclude shadows from certain lightsources on an object. Is this something we can hope for?

br
Henrik

[bepeg4d]

Hi,
please, update the plugin to 2.24.1-R3 stable or 2.24.2-Test 5.2 and give to the "Surface brightness" a try
ciao beppe

[HSR]

Hi
I just uploaded both the stand-alone and the c4d plugin to the latest version (OctaneRender_for_C4D-2.24.1-R3). But I still do not have the option for surface brightness available... Any ideas?

[bepeg4d]

Hi,
sorry, my mistake
you need the 2.24.2 for the "Surface brightness" option, sorry again for the confusion.

ciao beppe