calculating volume from 3d topo

Hello,

I have received a 3D Topo survey and I am wanting to calculate the volume of a reservoir. The reservoir is a closed polyline and the existing ground levels are points. I converted the ground levels into a triangulation surface and then i extruded the reservoir polyline beneath the ground surface, with the intention of using either the subtract or slice command so the reservoir would sit flush with the surface, so I could then use massprops command to calculate the volume of the reservoir. However, this is just not working for me. Neither subtract or slice are doing anything. Any suggestions? I would post the cad drawing but it is too large.

Thanks in advance

Wouldn't contours be required? You're expecting someone here to figure that out for you?

Wouldn't contours be required? You're expecting someone here to figure that out for you? BTW...since you don't have a surface nor a solid how did you expect the Subtract and/or Slice commands to work?

I am not sure how you managed to read my post about the subtract and slice command. But completely miss where I said I created a surface from the points/blocks and extruded the polyline into a solid.

I didn't post the drawing after I created the surface and solid as like I said the drawing was too large to post. So I posted the raw data, as mentioned.

Upload the drawing to a file sharing website like Dropbox and post a link to it here.

Well? What's the holdup?

If you have all your points as a solid surface then create a 2nd surface say a square bigger than the area using a pline with elev set to water level extrude it higher than highest point level then just subtract from surface mass prop should be answer. Its a obvious function of CIV3D.

This is a sure and much easier Civil 3D operation. You have your Topo - create a surface. And its easier now you have your reservoir sizes (closed Polyline) and also comes with existing ground levels. I'm assuming that the topo received is the existing and your reservoir is new (design). If they are separate, then create 2 different surfaces and compare.

This is a sure and much easier Civil 3D operation. You have your Topo - create a surface. And its easier now you have your reservoir sizes (closed Polyline) and also comes with existing ground levels. I'm assuming that the topo received is the existing and your reservoir is new (design). If they are separate, then create 2 different surfaces and compare.

Just seen this, thanks for this acemasi. I created two surfaces (one for the existing ground and one for the flat top of the resevoir) then created a 3rd TIN volume surface and set the base and comparison surface.