Bug Report: CoronaDecal — any non-zero Bend value causes decal to disappear completely on render
Environment:
Corona Renderer 14
3ds Max 2026
OS: Windows 11 (if applicable)
Description:
When using CoronaDecal with both Bend parameters set to 0, the decal projects correctly onto the target object and blends with the base material as expected. However, as soon as either the Horizontal Bend or Vertical Bend parameter is changed from 0 to any non-zero value — even as small as 0.1 degrees — the decal completely disappears from the render. No partial result, no degraded quality — the decal is simply not visible at all.
Steps to reproduce:
Create any object (e.g. a Cylinder)
Create a CoronaDecal, position its box outside the object so it projects inward onto the surface
Assign a texture to the decal — confirm it renders correctly with Bend = 0
Change Horizontal Bend OR Vertical Bend to any value other than 0 (e.g. 0.1)
Render — decal is no longer visible
Expected behavior:
Decal should project onto the surface with a curved shape following the bend parameters, similar to how it wraps around cylindrical objects.
Actual behavior:
Decal disappears entirely from the render as soon as any Bend value is non-zero.
Workarounds tried:
Increasing Depth value — no effect
Different object types (primitives and Editable Poly) — same result
Both Horizontal and Vertical Bend independently — both cause the same issue
Impact:
This makes the Bend feature completely unusable for wrapping decals around cylindrical products (bottles, cans, tubes etc.), which is one of the primary intended use cases for this parameter.
Just a note for support / devs - this definitely used to work, as it was exactly how it was used in the release video.
It also seemed to me that this worked for me in some of the previous versions, but in version 14 I see this picture, this thing is very useful, but the whole point of its usefulness is lost when it is impossible to bend around cylindrical objects, since this is the most common scenario in working in subject visualization.
When you’ll be fixing it, please also add an option to bend decal in Z direction ;]
BTW, i tested bent decal in Corona 14 Update 1 Hotfix 1 and it works just fine, so the bug is probably fixed and it’s just a matter of updating to the latest.
Hi,
Please send the scene (or these specific objects) over, so we can check it, it looks like a clear bug.
This is not observed in special cases or with special geometry; it is a systemic problem that occurs under any conditions and with any objects, even with standard primitives like cylinders. I’ve created two primitives in an empty scene, a plane with a cylinder on it, and two decals next to it. I’ve bent one of the decals to wrap around the cylinder, and the other decal is flat with a straight projection. The flat decal on top projects text onto the cylinder using a black-and-white mask, but the decal that wraps around the cylinder doesn’t project text using the mask. I honestly have no idea why this is happening, so I decided to post it on the forum.
CoronaDecal Bend parameter breaks projection.zip (89.8 KB)
God, it was so simple, so banal )))
In any case, thank you so much. This little detail was so annoying that it overshadowed the benefits of the decals.
Glad that it helped.
Nevertheless, it is not expected behavior and a bug reported.