Summary

Thankyou for having a look at this. Using the latest Nightly build, my problem seems to still exist even making a new scene and following the steps I outlined above.

Attached are some screen shots illustrating my steps. 

Are there any logs or such that may highlight a conflict with other existing installed plugins? There are Ornatrix messages being logged to the MAXScript Listener, but nothing that would suggest an issue.

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Attached Files:

3dsMaxVersion.PNG (16536 bytes), OrnatrixVersion.PNG (40299 bytes), reset.PNG (97635 bytes),

Update: If I BOX the surface comb modifier into a groom, the Sink's maintain their Length Multipliers.

The studio where I work currently only has 3ds Max 2021.1 and the project I'm working on has a deadline quickly approaching. Are you able to test using 3ds Max 2021.1?  

Thankyou for all the replies.

@Jeordanis Figuereo,
I tried resetting 3dsMax preferences following the manual guide here: i.e getting max to remake the ENU folder. I tried this on 2 separate computers both running the same Windows OS and 3dsMax 2021.1. The issue still persisted.
https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/Resetting-3ds-Max-3ds-Max-Design.html

@EPHERE, with the Surface Comb algorithm set to "Triangulation" the Sink property 'Length Multiplier" does not change the strand length; only if its set to Mesh Vertex. This property is not really explained in the 3ds Max docs, and the Maya docs suggest that Mesh Vertex is the recommended method.
https://ephere.com/plugins/autodesk/max/ornatrix/docs/8/Surface_comb_modifier.html
https://ephere.com/plugins/autodesk/maya/ornatrix/docs/3/Surface_comb_operator.html

@IvanKolev, I see that there are later security patches for 2021 which we could try as listed here:
https://help.autodesk.com/view/3DSMAX/2021/ENU/?guid=3dsMax_ReleaseNotes_updates_html
But as this will not be a small task to upgrade our render farm; I will proceed with the work-around of Boxing the Surface Comb modifier into a groom for now.
Also note I had issues with Surface Comb crashing the 3dsMax Backburner Network Submission, but this was also fixed by boxing the surface comb into a groom within the modifier stack.

I'm inclined to think its a 3dsMax version issue.

When I get time, can try the upgrade of 2021.1 to the latest 2021.3.17, but this will most likely be a next year task.

Kind Regards.

The latest nightly build fixed my Network Submission crash, but the Surface Comb's strands still forget their assigned Length Multiplier Values. My workarounds for this are either using length texture maps or Box surface comb into a groom.  

Kinds Regards.

Sorry for any confusion, this is two issues:

problem 1: When open an existing scene and add new sinks to a surface comb, existing sinks (arrows) all have their Length Multipliers set to 0.

problem 2: If I set individual sink(arrows) Length Multipliers to a value not 1.0, when open the scene next they are all reset back to 1.0

see attached screenshots illustrating problem 1.

I brought up problem 2 as they seem related to me.

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Attached Files:

SurfaceComb_CreateNewSink_after.PNG (222829 bytes), SurfaceComb_CreateNewSink_before.PNG (233168 bytes),

Thankyou, tested the nightly build 35404 and this has fixed these problems.

<span>Really appreciate the time and effort of your dev team to solve these issues.</span>

Kind Regards.