topic Re: Any way to create a 3D solid from 3d Polylines? in AutoCAD Forum

Any way to create a 3D solid from 3d Polylines?

lais.r.f — Mon, 05 Jun 2023 13:10:10 GMT

Hello,
I have to 3D polylines from which I would like to create a 3d solid. I tried the command Loft which gives me a 3D Face between the two polylines, but I am looking to create a solid 3d volume, or rather, what I need is to find out the volume of the space between these two 3d-Polylines. Any way I can go about that?

Re: Any way to create a 3D solid from 3d Polylines?

Washingtonn — Mon, 05 Jun 2023 17:19:30 GMT

If you are trying to determine the volume in order to calculate cut/fill for say a road/driveway and you don't have access to other software more suitable for the situation, then the following video link may give you some idea as to manually calculate the volume using cross sections. With only two polylines, you will be making assumptions about what is within and outside of each polyline.

LINK: https://www.youtube.com/watch?v=TfqNK4v73nk&t=534s

Re: Any way to create a 3D solid from 3d Polylines?

leeminardi — Mon, 05 Jun 2023 19:03:52 GMT

I manually created 3dfaces for the entire model. I first created the 3dfaces for the two 3dpoly's and then for the connection between the two poly's. You have to be careful to reference all the vertices of the 3dpolys when creating the faces. Also, be sure that you use only 3 vertices for the 3dfaces. If they have 4 vertices then the face may not be a flat plane. Once you have the volume defined as 3dfaces you can then use the region command to convert them to regions which can be used by surfscult to create the solid.

The attached model includes a 3dface model and a solid model.

Re: Any way to create a 3D solid from 3d Polylines?

lais.r.f — Tue, 06 Jun 2023 06:57:12 GMT

Thank you, that's how I would usually calculate earth masses and I was wondering if there was an quicker way to get there from the 3D models since I have the 3d Polylines anyway. Thanks for taking the time for your reply!

Re: Any way to create a 3D solid from 3d Polylines?

lais.r.f — Tue, 06 Jun 2023 06:58:53 GMT

Thanks! I had tried the 3D faces, but I believe I made some 4 vertices faces which might be why it didn't work. Thanks for your detailed reply!