How to make a smaller surface

[LyleHardin]

I've downloaded a DEM and made a surface from it creating a HUGE file. I only need about an eighth of that area. How can I crop the surface to be a smaller area?  I realize I can create a boundary, but I really don't need all the data outside the boundary.... I want a smaller file so it doesn't have to create one of those *.mms files.

Surely I don't have to export the boundaried area as triangles to a regular ACAD file, then make a surface from those triangles... do I? Not that it's that big of a hassle, but seems like a roundabout way of doing things.

[sboon · Accepted solution]

Use a data clip boundary.  You may have to change the order of operations in the Definition tab of your surface properties however.

[LyleHardin]

That did it. Thanks. It's amazing what's "hiding" under those flyout options. And yes, I did have to move the boundary to the top of the heap in the Surface Properties > Definitions tab. Thanks again.

[mathewkol]

Steve's advice is likely the correct one for your situation, but also keep in mind, if you need the huge surface, but want another dwg which includes a smaller portion, that there is a crop surface tool as well.

[ian_mcgregor]

Hi

Instead of duplicating the surface (data) and cropping a copy, how about using data shortcuts for that. Keep the source drawing with the superset of the required data and data clip in a shortcut reference drawing, then you only hold the data once get the best of both worlds and keep the drawings dynamic to a single data source.

Just my $0.02 on a hypothetical scenario 🙂

[sboon]

Hello Ian,

Not sure that I understand what you're proposing.  If the OP uses a data shortcut to get the surface from another drawing then he will get the entire surface referenced in.  I'm not aware of any way to apply a data clip boundary - or any other type of edit to a referenced surface.

Please clarify.