Use the range slider to adjust the range of values in your motion vector AOV. Higher values are needed for scenes with fast-moving objects. Lower values are more suitable for scenes with objects moving more slowly. The default value of 20 is usually appropriate for the majority of scenes. When inspecting your RMSB Motion Vector AOV pass in the compositor, you'll need to set the slider to a value that returns no black pixels i.e. the image should appear as tones of red and green only. Failing to set the sensitivity slider correctly may lead to artefacts in RSMB so be sure to pay attention to this setting.

For maximum flexibility and to save headaches with having to re-render your sequence, in the case of setting this slider incorrectly. We suggest saving the regular Cycles motion vector pass to disk, along with the rest of your passes/AOVs. That way should you need to adjust the RSMB Motion Vector AOVs node to get the correct output after rendering, you will still have the ability to do so.

The exported RSMB motion vector AOV will work with any third party tool supporting Reel Smart Motion Blur. Including: After Effects, Blackmagic Fusion, Nuke, DaVinci Resolve, Media Composer, Baselight, Final Cut Pro, Premiere, Natron, Apple Motion etc. The download files also include an installable macro .settings file for a node group you can use directly within in Blackmagic Fusion.

The new way
If you save the included blend file to your asset library folder, it will be automatically saved to your asset browser. Which will also make it available in a new section of the Compositor's context menu, under Compositing > RSMB_Motion_Vector_AOVs_v1.4

The old way
You can also append the node group from the supplied product file to any Blender project using the usual append method. The node group will then be available in the Compositor's add group menu. Be sure to enable the Vector pass under the View Layer Properties tab though first.

• Are you rendering your Motion Vector AOVs to 32 bit EXR?
  Due to the data they contain, motion vectors require you to render to a linear format like EXR, ideally in full float (32 bit colour) for the highest accuracy. If you're rendering to a non-linear format such as JPEG or PNG, RSMB won't be able to interpret the data in the image correctly and you'll end up with incorrect motion blur and visual artefacts.
  
  
• Is there any black visible in your Motion Vector AOV?
  When inspecting your Motion Vector AOV pass in the compositor, you'll need to set the range slider to a value that returns no black pixels i.e. the image should appear as tones of red and green only. Failing to set the sensitivity slider correctly may lead to artefacts in RSMB, so be sure to pay attention to this setting and do some tests with frames from the start, middle and end of your sequence.
  
  For maximum flexibility and to save headaches with having to re-render your sequence, in the case of setting this slider incorrectly. We suggest saving the regular Cycles motion vector pass to disk, along with the rest of your passes/AOVs. That way should you need to adjust the RSMB Motion Vectors node to get the correct output after rendering, you will still have the ability to do so.

Since RSMB expects motion vectors to have a value of 0.5 in the alpha channel. The node group requires both an alpha input *and* a vector input, which allows this value to be set correctly. An alpha input can be extracted from your beauty pass/AOV or you can use the dedicated alpha pass/AOV.

This is one of the limitations of 2D motion blur. When applied to full frames RSMB usually works best with relatively subtle motion blur. However to avoid hard edges when applying heavy motion blur, you can separate your objects via render layers or with Cryptomattes. Then apply motion blur to each render layer individually. Allowing you to fine tune your composite as needed.

Yes! Since the release of Blender 4.0 and EEVEE can now export a vector pass as well as Cycles. The addon will work with both EEVEE and Cycles.

No, the standard motion vector AOV created by Cycles isn't compatible with RSMB.