Community
Arnold for Cinema 4D Forum
Rendering with Arnold in CINEMA 4D using the C4DtoA plug-in.
cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

C4D Arnold HDRI/Ground Plane Reflection issue

3 REPLIES 3
Reply
Message 1 of 4
minidaz
603 Views, 3 Replies

C4D Arnold HDRI/Ground Plane Reflection issue

Hello all,

Hope everyone is well? I have a question around ground plane reflection with Arnold and C4D. No matter what options I try I cannot seem to get the correct perspective around ground plane projection reflection. I have looked high and low and so far only found Maya workarounds.

So far I have tried setting up a Ray-Switch network identical to the Maya 2020 solution. Turned on and off shadows in the Tag parameter options for the Shadow-Matte (with and without Ray-Switch Network) which resulted in weird anomalies (pic 2 and 3), despite that often mentioned in posts/tutorials as the go to solution. It appears the only way I can get close is with the Ray-Switch which Arnold for C4D appears to be missing a 'perspective type' option in the projection node? (See Ray-Switch Shader below).

Any help would be appreciated!


Close but no cigar!

Incorrect perspective reflection? (Using Ray-Switch with Spherical type) No 'Perspective type' option available?

6772-ray-switch-render.jpg


Settings:

Tag Parameter shadow option set to 'on', Correct ground plane reflection but black area shows.

6773-shadow-on.jpg


Tag parameter shadow option set to 'off' HDRI and ground-plan competing against each other.

6774-shadow-off.jpg


Ray-Switch Shader Tree:

I designed 2 test options with 1x being an RGBA Projection, The second a Camera Projection shader. Both identical render results in (top pic).

6775-ray-switch-tree.jpg


6776-projection.jpg

Labels (2)
3 REPLIES 3
Message 2 of 4
lee_griggs
in reply to: minidaz

Have you tried offscreen_color?

Lee Griggs
Arnold rendering specialist
AUTODESK
Message 3 of 4
minidaz
in reply to: minidaz

Hello Lee,

Thanks for your feedback! I tried the suggestion from the Arnold but unfortunately I have ended up with another issue in the process. When I apply the background image to the either the Offscreen Colour Link or Offscreen Colour slot it seems to solve the issue but I end up with a sharp edge of the ShadowMatte Plane that is not matched to the HDRI (Circled in red) and a secondary image of the background image (circled in blue)? So in reality I have 3 reflected images on the chrome sphere. 1x HDRI, 1x Ground Plane, 1x Ground Plane in Offsrceen slot?

Is their a way to feather the edge of the ground plane reflection? Or am I looking at this the wrong way?

6891-offset-color.jpg

6892-offset-colour.jpg

6893-shadow-matte.jpgCheers

Darren

Message 4 of 4
systembolaget
in reply to: minidaz

Can't you map the ground plane with a transparency/opacity map to feather it out?

Can't find what you're looking for? Ask the community or share your knowledge.

Post to forums  

Autodesk Design & Make Report