MotionBlur renders wrong with directional rect lights (looks only right without MotionBlur)

[BeneZ]

Hello,

I have several times experienced a bug, so today again:
When I render motion blur with a Rectangular Light (which is directional 0,9), then the light is just like a hard projection on my object.

You can see the attached rendering of a grey plane:
You see clearly the picture of the umbrella on it, which is the HDRI image.
The same rendering without motionblur (velocity) enabled looks fine as expected.

I'm not exactly sure, what leads to this failure (if the vray layered tex is incompatible maybe), but I could provide a scene...

Thanks for help

[hermit.crab]

Could you send the scene (or attach it here) via the contact form so we can take a look? Mention me in the subject and include a link to this thread in the message.

[BeneZ]

Thanks, I did...
I hope it worked, because there was no confirmation from the website.

[hermit.crab]

Thank you for the report and the provided scene. The issue occurs when a textured light has animated intensity and motion blur is on. I've logged it (internal bug-tracker id: VMAYA-10524) for developer analysis. In your specific scenario, the highly scaled lights contribute to the visibility of the issue.

[BeneZ]

Thank you for reply!
It is maybe very related to another issue (which I haven’t reported properly to you as I remember),
that lights with a color multiplier do sometimes „forget“ to reload the color.
I had written it here on the forum 2 months ago, in case you can see my forum threads history, you will see it easily.
I can try also to provide the other scene once.
(These are both really long-time bugs)