OTOY Forums

Hi,

Apologies in advance in there if this has been posted already.

I have a simple scene with a typical studio setup lit with an HDRI. i would like to be able to add a material to make the background object catch the shadows and pass this correctly to the alpha channel along with the object being rendered. In mental Ray i used to be able to do this with the 'Matte / Shadow / Reflection material'. it was quick and easy to isolate an object with its accompanying shadow for comping. I noticed the diffuse material has a 'Shadow catcher' tag but this didn't seem to achieve the result - will read up more on this.

Help greatly appreciated.

Will.

Hi Dottedline,
use diffuse material with shadow catcher enable.
could this help you?
Regards

Thanks,

I found you also need to enable the alpha channel in the Kernel tab to get it / save it out.

Cheers.

Hi Again, got this working fine, out of interest really id like to have the option to catch indirect light contribution etc, reflection etc. Currently it only seems only to catch shadows. Probably something simple Ive missed. input appreciated!

Hi I also have the same question.
I creating a test scene to integrate a 3D glass of whisky into an empy table picture, and I can't find the way to have reflections integrated.
Shadows work fine, but not reflections.
I saw some videos of Octane for Cinema 4D but apparently rhino's plugin has not all the same features, am I right?

I creating a test scene to integrate a 3D glass of whisky into an empy table picture, and I can't find the way to have reflections integrated.
Shadows work fine, but not reflections.

I am not sure exactly what you are trying to do here, however you can render the reflection passes via the Render Passes, and also assign Render Layer id's to the glasses to include/exclude them from the various light passes. I recommend having a read of the Octane Standalone manual at docs.otoy.com for more details.

Thanks

Paul

Hi Paul,

Sorry i realised id posted another topic in relation to this so deleted and added back in here - this follows on from an old post.

To recap my earlier message:

I was wondering how to enable an octane material to not only catch shadows but also secondary bounced light and colour from HDRI’s etc for compositing. Currently enabling the shadow catcher in a diffuse material does sort of work but it only seems to produce a ‘black’ shadow and not the subtle bounced colour, more of a direct shadow if that makes any sense. I’m pretty sure I used to use a ‘matte shadow material’ in mental ray years ago that would essentially catch everything on its surface that was direct & indirect. Is there something I need to tick on etc? This tutorial (https://www.youtube.com/watch?v=mST_-dmZYHc) in C4D relates as he adds a diffuse material and set it to 'matte' - this is what i woudl have done in MR essentially.

For example on this sample scene there is a white background with a red ball lit by an HDRI. The shadows are soft, subtle red colour bounce etc etc.
I then change the background to diffuse material, switch on shadow catcher and enable alpha channel in the kernel settings.
The render show a stark dark shadow, no subtle subtle bounced colour etc but does contain transparency
Is there a workflow for a simple matte material that can catch the shadows & other subtle Illumination on the background, or is the workflow to use render passes? if so, how do i enable the alpha for the layers? I may be getting muddled up with the shadow catcher setting & render passes - guidance appreciated!

Cheers

Will.

Hi Will. As this is not a specific plugin question (and I don't know the answer), I suggest posting it in the general Octane forum.

Thanks

Paul

Hi Paul,

It's specific to rhino plug-in, sorry if that was unclear. I'm unsure of the settings to use to get the results I need. I can repost if that helps.

Thanks

Will.

Dottedline wrote:Hi Paul,

It's specific to rhino plug-in, sorry if that was unclear. I'm unsure of the settings to use to get the results I need. I can repost if that helps.

Thanks

Will.

Can you please post this question in the general Octane forum.

Thanks

Paul