'Trimmed surface' to 'Surface'

Hi, I was having trouble figuring out how I could possibly convert a Pentagon (Trimmed surface) to a regular surface. I want to convert it to a surface so that I can later add the same to Grasshopper.

Also could is there a way I could do the same for any other polygon? (Trimmed surfaces)

Hello - no - untrimmed surfaces have four edges -in some cases these can be compressed to a single point so that the object appears to have only two or three edges, but in any case never more then four.


Hi Pascal, thanks for the reply. Would you by any chance know how I could input a trimmed surface into grasshopper then?

(I would like to get my Pentagon into Grasshopper to use it on the lunchbox plugin which only takes a surface as an input.)

Probably not the answer you are looking for but you might want to look into this:

Also, I made this pentagon-like single surface using _NetworkSrf. The down side is one of the corners ends up being a bit rounded. This may opr may not be compatible with your design.

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If you feed it a trimmed surface, Lunchbox will just revert back to the underlying untrimmed surface, which makes complete sense because that is where the isocurves reside.

If it were me, I’d probably split one of the curves and make two surfaces with mirror symmetry. Lunchbox can handle that just fine, although it will not have rotational symmetry of course.

Just to add, if you did want rotational symmetry, make 5 surfaces (using NetworkSrf with 3 curves each), then feed these into Lunchbox:

i am not using lunchbox - not sure what the effect of a single rotational surface is:

to build a surface like this (it will be Degree U/V 1/1) disable
_creaseSplitting (= off / Disable)

and then draw a pentagon (and an optional line) use
_railRevolve (line , pentagon)
_extrudeCrvToPoint (pentagon)

would be nice to see the lunchbox result in this thread / topic

best tom


Works very well indeed. Here is the result for extrudeCrvToPoint. I’d not come across this before, so always nice to learn something new. Thanks.

@jitmit999 Make sure to set the uCount (or vCount depending on the surface direction) to a multiple of 5 of course.

Woow! Thanks for this :slight_smile: