Turbo Talk => Problems => Topic started by: PAYRE on November 21, 2018, 07:46:30 PM

Title: Volumes from Lofted Solids
Post by: PAYRE on November 21, 2018, 07:46:30 PM
I'm using TC Pro Platinum 23.2 to calculate volumes for an excavation. There is an earth ramp proposed with a tappering road surface so the best way I've found to model this is by lofting the road outline to the base outline. My problem is that the resultant loft does not have a volume in selection info. The loft converts simply enough to an ASIC Solid, but again no volume. I can delete the solid from a box of known volume but the result has the same volume as the original box. I can intersect the solid with other solids but again no volume.

Hoping someone has a simple solution.
Title: Re: Volumes from Lofted Solids
Post by: John R on November 21, 2018, 08:14:09 PM
Select the Loft object, then click on the "ƒ" icon in the Selection Info palette. Expand the "Solid-state Physics" property to find the "Volume" and other properties.
Title: Re: Volumes from Lofted Solids
Post by: Henry Hubich on November 22, 2018, 09:14:06 AM
I'm using TC Pro Platinum 23.2 to calculate volumes for an excavation. There is an earth ramp proposed with a tappering road surface so the best way I've found to model this is by lofting the road outline to the base outline. My problem is that the resultant loft does not have a volume in selection info. The loft converts simply enough to an ASIC Solid, but again no volume. I can delete the solid from a box of known volume but the result has the same volume as the original box. I can intersect the solid with other solids but again no volume.

Hoping someone has a simple solution.

If John's tip doesn't work, then perhaps the loft is actually a "sheet object": a zero-thickness empty shell. To check for this condition, 3D-Slice the object approximately in half, select one of the halves and render in a Draft mode, and look at it from a viewpoint that shows the sliced face. If the object is hollow, then Undo the slicing operation, select the object, and go to Modify>Modify 3D Objects>Create Solid>From Surface.

Henry H
Title: Re: Volumes from Lofted Solids
Post by: murray dickinson on November 22, 2018, 04:48:57 PM
A variation on Henry's advice is to subtract a sphere that intersects the surface of the loft.  If it's solid, the subtraction leaves an imprint semi-spherical surface sealing it, if it's a surface the subtraction leaves a hole to the loft's interior.  It's worth trying SAT healing to solidify problem objects like that.
Title: Re: Volumes from Lofted Solids
Post by: PAYRE on November 27, 2018, 08:43:04 PM
Thanks all,
As sugested it appears the object created with the loft is zero thickness shell of the sides only, as defined by the open top and bottom 3D polylines. Strangely after exploding it showed as a solid, but using Modify>Modify 3D Objects>Create Solid>From Surface would suggest that it was an open shell.

After some experimenting it turns out the problem is that my top sloping 3D polyline was not in one plane, there is twist as the top of the ramp due to a slight S shape. I re-made two lofts for different parts of the ramp approximating the slope twist with two different top planer polylines. The resulting loft was also a zero thickness surface, but it converted to a solid using Modify>Modify 3D Objects>Create Solid>From Surface.

Thanks again, much appreciated