Animated Mask Modifier creates artifacts when property "invert" is being toggled
Closed, ArchivedPublic

Description

System Information
Windows 10 Home and GeForce GTX 1060 with Max-Q Design

Blender Version
2.79 Official Release 5bd8ac9{F845533}

Short description of error
When "Mask modifier" is on there are some artifacts on the rendered image when property "invert" toggles,
but when Mask Modifier is applied (for invert on or off), everything is OK.


Exact steps for others to reproduce the error
Render 32'th frame, and you will see artifacts, to find them easly apply the modifier and then render again.

Details

Type
Bug

This is a known limitation of Motion Blur that modifiers altering geometry may have an undesired impact.
https://docs.blender.org/manual/en/dev/render/cycles/settings/scene/render/motion_blur.html#options

Mask modifier is not mentioned as an example but warning is valuable for it.

You could choose a Motion Blur that starts on frame instead of centered on frame to avoid problem at specified frames.
Or you could try to animated red/green lights by using animated textures that don't change the geometry.

Joshua Leung (aligorith) closed this task as Archived.Sep 25 2017, 2:50 AM
Joshua Leung (aligorith) claimed this task.

Closing. This sounds like a known limitation with geometry-altering modifiers and motion blur.

@Aaron Carlisle (Blendify) : Maybe the docs should be updated to also note that the Mask Modifier may also cause similar problems?

Yeah sure, I will put it on my todo for Wednesday.