Difference between Extrudesrf and Extrudecrv?

first of all im so new to rhino and im wondering what is the difference (if i have 2d rectangle) between select the rectangle and press planarsrf then extrudesrf and extrudecrv immediately ?

Hi Jordan - - in Rhino a rectangle is a curve - ExtrudeSrf will not allow it to be selected as input. A rectangular surface however - like what you’d get from the Plane command, or by running the PlanarSrf command on a rectangle, is valid input for ExtrudeSrf. If you run ExtrudeCrv on a surface, it will let you select the edge curves of the surface but not the surface. Note both commands have a command line option for closing the resulting object (Solid=Yes/No). Curves must be closed and planar in order to create a closed extrusion with Solid=Yes.


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completely got it, Thank Pascal

The result of the ExtrudeSrf command - polysurface.
The result of the ExtrudeCrv command - extrusion.
Extrusion is easier than polysurface. Is not it?


Hi - I take it that you mean “lighter”. That is true but it is unlikely that you will notice this unless you have several thousands of those objects in your file. Also, as soon as you trim an extrusion, it automatically becomes a polysurface.

In my file there are 1180 closed poly-surfaces and 1180 closed light extrusions of the same shape.
I put these heavy in one file and noticed that its size is about 22970 KB.
I put these lights in another file and noticed that its size was about 2320 KB.
For example, I can see that the lights are much lighter than the heavy ones.

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