Sheet keeps "hidden" face after being trimmed

[ErkiPerki]

I have a surface created with FitSurface from points which I then cut with TrimSheet. When I place a point using U&V parameters on the new surface (Trimmed sheet), It can go outside the newly cut surface. I want the U&V only to refer to the new surface and it doesnt go beyond.

Why does this happen?

 

[cowski]

The trim sheet command keeps the underlying pole structure of the surface and just trims off a portion. The snip surface command will also trim a sheet body to your input geometry, but it will modify the underlying pole structure.

https://docs.sw.siemens.com/en-US/doc/209349590/PL20231101866122454.modeling/shp_snip_surf_related_commands

If you don't have access to support center documentation, search for "Snip Surface: related commands" in the NX modeling help.

 

[ErkiPerki]

The trim sheet command keeps the underlying pole structure of the surface and just trims off a portion. The snip surface command will also trim a sheet body to your input geometry, but it will modify the underlying pole structure.

https://docs.sw.siemens.com/en-US/doc/209349590/PL20231101866122454.modeling/shp_snip_surf_related_commands

If you don't have access to support center documentation, search for "Snip Surface: related commands" in the NX modeling help.

It looks like it works better in that regard. Although Snip seems to produce some problems because the boundaries have to be a certain way...
It just seems to say "Unable to build surface" for some geometries.

 

[cowski]

In general, I don't use snip surface because of how it changes things. I usually use trim surface or trim body.
What exactly are you trying to do? What will this point on face be used for? What is driving the location of this point? There might be a better way to get the desired end result.

 

[Toost]

The shape of a surface and the boundaries are , if trimmed, separate equations. The trimming does not affect the shape eqations.
Snip will attempt to recreate the shape without the trimming operation, which isn't always possible.

Regards,
Tomas