Rendering Clear Plastics with Backplate

[topsecretagent]

Hello!

Could someone please help explain why clear plastic materials are showing a dark area (on the right side) when using a backplate image? This doesn't happen when rendering on a color background.. adjusting ray bounces does nothing. Global illumination is on.. I can't seem to find any information regarding this issue! Anyone else encountered this?

Any help appreciated!!

[kiarash.tamizkar]

it is because of thickness of glass and Fresnel effect ,its normal

[RRIS]

Does it look any different when changing the material to solid glass?

[Will Gibbons]

It's because they're reflecting the dark areas in your HDRI (a backplate doesn't get rid of HDRI reflections). You could use this image as the background of your HDRI and then the dark areas would be colored to match your HDRI instead.