Topographical Meshes

[Anonymous]

I am having a problem subtracting one mesh from another. I am subtracting one (existing) topographical mesh from another (proposed) to evaluate volumes of cut and fill. They are a meshes of at least an acre in size. The meshes have depth. The meshes are fairly idetical except where I have made cuts and fills by moving the mesh's contour splines. The meshes are each on their own layers.

When I use solid element operation I can not get them to subtract. I have used layers settings, wireframe, etc. to no avail. Have tried opening new files and pasting into them with same results. I can create relatively simple meshes or slabs and they subtract just fine. I am feeling that the meshes are sharing too many vertices in common...

My work around has been to just calculate volumes of each and subtract manually with calculator but doesn't help me discern between cut and fill, only net change.

Thanks

version 9
pc pent 4 3000
1300 ram
xp pro

[Anonymous]

I have been having better luck with my topo meshes. It has been working most times now for me without having to displace the two meshes.

I cut and paste the Existing & Proposed meshes into a new file. I select only the areas with grade changes with the marquee tool.
In the 3d window I do the S.E.O. I make sure that the operator's layer is in wireframe and that both meshes have identical depth settings.
I have stopped using bezier splines for the contours. I use only angled polylines. It looks fine printed and is actually much easier and faster to edit. I just add more angle points to make the line look more curved. The splines (curves) seemed to make the meshes too complicated?

Good luck,
Greg

[Anonymous]

g.h.design wrote:
The splines (curves) seemed to make the meshes too complicated?

That sounds like it.

You can still use the splines and keep the complexity low by adjusting the magic wand settings.