I thought I understand how to read Geometry Spreadsheet at least for SOP. However, when it comes to DOP, it seems everything I've learned is thrown out of the window.

For example, I have a Vellum Constraint Property DOP in Vellum Solver SOP:



I set restlength to 1. However, it doesn't reflect on the Geometry Spreadsheet at all. How could I view the values that are set by Vellum Constraint Property?

you are setting for "stretch" group, do the primitives shown in your spreadsheet belong to that group?

DOP spreadsheet will show you data at the end of current timestep so if you are looking at the correct geometry data and modified prims, you should see the updated values

tamte
you are setting for "stretch" group, do the primitives shown in your spreadsheet belong to that group?

Yes, they do. And even after disabling "Group" parameter, the change is still not shown in the spreadsheet.

tamte
DOP spreadsheet will show you data at the end of current timestep so if you are looking at the correct geometry data and modified prims, you should see the updated values

Well... perhaps I should report this as a bug...

it's unlikely to be a bug, at least in my experience the spreadsheet is reliable

are you on the first simulation frame by any chance? in Vellum sourcing happens after forces are applied so any freshy sourced constraints will not receive your new restlength on that timestep
so maybe try plugging your node to SOURCE Output node, since that one is evaluated after internal source

tamte
it's unlikely to be a bug, at least in my experience the spreadsheet is reliable

are you on the first simulation frame by any chance? in Vellum sourcing happens after forces are applied so any freshy sourced constraints will not receive your new restlength on that timestep
so maybe try plugging your node to SOURCE Output node, since that one is evaluated after internal source

Oh you're correct. Simulating it for one frame does update the values in Spreadsheet.

I'm still quite confused about when I should connect to FORCE and when to SOURCE tho.

raincole
I'm still quite confused about when I should connect to FORCE and when to SOURCE tho.

roughly, FORCE is evaluated Pre-Solve, SOURCE is Post-Solve
for more specific details you can look inside of the solver if you are interested when exactly each of them evaluates