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Christiaan

How to make a solid out of two polygons/polylines

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I want to calculate the volume of a water swale.

 

I have the top edge shape and the shape of the base, both in the form of polygons. And I have their distance apart vertically. How do join them into a solid (for a topped off cone shape) so I can measure the volume directly?

 

Am I right to think I should be able to use the Loft tool for this?

Screen Shot 2017-01-18 at 16.33.38.png

Edited by Christiaan

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There may be a more elegant way of doing this (I get shown up frequently on the forums with questions like this), but the method I can think of immediately:

 

1) Convert both polys to NURBS curves. Copy these curves off to the side or duplicate them in place and then hide them, we will need them later.

 

2) Loft tool in the No Rails mode, select both NURBS and then the resulting lofted surface should give you the side walls. If they need to not be straight then a profile curve will need to be added and another mode of the Loft tool used to make the sides.

 

3) Model > 3D PowerPack > Create Surface From Curves on the top and bottom NURBS we saved from earlier to get you the top and bottom faces.

 

4) Make sure both the top and bottom faces are snapped into place perfectly at either end of the sidewall NURBS, then select the wall and both top and bottom faces and use Add Solids.

 

I am pretty sure you can use Model > Volumetric Properties on the resulting addition to get the surface area and volume, if it doesnt work, you may need one more step of converting the Solid Addition to a Generic Solid with Modify > Convert > Convert to Generic Solids.

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Awesome, thank you Jim. I skipped step 3-4 and and just chose "Create Solid" in the Loft Creation window.

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When you first do the loft, the dialog that pops up will have a little connecting line, often its heavily angled where it should ideally be set straight:

Good:
Screen Shot 2017-01-18 at 12.32.24 PM.png

Bad:

Screen Shot 2017-01-18 at 12.32.32 PM.png

 

That MIGHT be what yours is doing. If that doesnt work, then I think selecting one of the NURBs (Not both) and clicking Reverse Direction in the OIP can fix it too.

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1 hour ago, Christiaan said:

Awesome, thank you Jim. I skipped step 3-4 and and just chose "Create Solid" in the Loft Creation window.

 

Forgot about that entirely, thank you! Makes it much simpler.

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Great little thread.  This is the kind of stuff I'm looking for each day.  Unscripted tips and tricks.

Edited by Markvl
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