Directional blur node doesn't clamp value if using driver
Closed, ResolvedPublic


System Information
Win7 32 bit

Blender Version
Broken: 2.78a

Short description of error
BI viewport doesn't render until use limits for a driver.

Exact steps for others to reproduce the error
Add driver to X coordinate which has value out of 0-1 and try to viewport render. Or in .Blend file you can mute/unmute "Limit modifier" for driver.

Related Objects

Dalai Felinto (dfelinto) triaged this task as "Confirmed" priority.Jun 12 2017, 4:01 PM

Confirmed. Note to other testers on how to test it:

  • Load file, enable auto-run scripts
  • Switch viewport to rendered
  • The viewport has nothing rendered.

Now move the cube on its Z axis. When the coordinate is within 0/1.0 range, the viewport render shows something. Otherwise it "freezes" the render again.

Even if you replace the driver expression by directly typing the value (0.2, 1.4, ...) you get the same issue.

It seems like the compositor is expecting a clamped value, and since driver gives you something else, it is blocking the render in viewport.

This is not related to the directional blur node. Here is an even simpler file using another node:

Note that the compositor node is not even being used.

(for the records the original claim that clamping is the issue could be solved with P494, but RNA is already clamping the values before we get to the compositor, so this patch is uneeded)