[quote user="Jon Summers"]Perhaps it's simplest to use mdlKISolid_elementToBody2 followed by mdlKISolid_capSurface. Does mdlMeasure_volumeProperties work with the resulting KI solid?[/quote]
Yes, you can get the volume from a KI solid...but I always try to avoid unneccessary BRep conversions.
[quote user="Jon Summers"]I don't see a function mdlSurface_convertToSolid, so what approach do you recommend? I guess that it needs end caps as well as, or as part of the process of, converting to a solid.[/quote]
I assume this is V8i, I didn't look for an api function, but if you know you have a closed profile you can a SURFACE_ELM into a solid by just setting ehdr.type to SOLID_ELM. That's all the "Convert to Solid" tool does when you pick a SURFACE_ELM and specify "primitive solid" as the desired type.
HTH
-B