I'm trying to have a grease pencil fade in and out over a number of frames. I'm able to get this behaviour in the blender viewport, but not when I render. I've created a minimal example which is available here:

The minimal example has a grey square, drawn in the default "Lines" layer of the default "Stroke" grease pencil. The opacity of this layer is set to transition from 1 at the start to around 0.1 at the end. When I play in the blender viewport, I see a smooth transition. When I hit "render animation", I see no change in opacity for different frames, and the rendered opacity matches whichever frame I have selected in the UI. "Render animation" will still correctly render motion, if I add location keyframes, but the opacity still behaves in the described manner.

Is there a way to make the render output respect the transition between opacity values?

Steps to create the minimal example:

  1. Draw a square in a new 2D animation
  2. Set end frame to 20 in the timeline
  3. Create a keyframe for the opacity property of the "Lines" layer, at frame 0
  4. Create another keyframe for the opacity property of the "Lines" layer, at frame 20
  5. In the graph editor, drag the opacity at frame 20 down to around 0.1

1 Answer 1


This appears to have been a bug in blender 2.81. The example above behaves as expected in blender 2.82.

  • $\begingroup$ Possibly better suited to a comment on question. Questions re bugs in blender are regarded as off-topic, and it is suggested they be reported to the official bug tracker. As mentioned it appears tho, this one has been fixed. $\endgroup$
    – batFINGER
    Mar 5, 2020 at 14:49
  • $\begingroup$ I initially wasn't sure if this was a bug, or a misunderstanding on my part about how rendering works. Do you know of a more appropriate forum for discussing issues when I'm not sure whether there's a bug in blender or a problem with my use of blender? I'd like to respect the rules and etiquette of this site! Thanks. $\endgroup$ Mar 5, 2020 at 15:22
  • $\begingroup$ Wouldn't worry about it too much. The "powers that be" (other users) will decide if it be closed or not. Seems to me worth marking as about a bug, since it appears to be fixed and you were spot on, on method. (Hence the upvotes). When not sure, I would err on a question here rather than an official bug report too. $\endgroup$
    – batFINGER
    Mar 5, 2020 at 15:35

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