Mesh Tool - Maximum Contours or Nodes?

[Anonymous]

I am creating a mesh 1000' x 2000' by magic wanding the contours from an imported survey. Each contour has a gazillion nodes. I tried to first convert the contours to polylines or splines with fewer nodes but the magic wand set to wide/large tolerances had no effect; the resulting lines had all the nodes.

Not wanting to draw each contour, I decided to see if I could quickly snap out the mesh anyway. I was able get about halfway before the magic wand stalled. (I get the beep, but no resulting contour.) Elevations of each contour and at all corners are correct. I can add the rest of the contours manually, but I would like to avoid it. The image shows the mesh so far (dark) & the ghost story underlay (light). The underlay contains only complete polylines (no breaks.)

Questions:
1. What is causing the mesh to bog down? Number of nodes? Too many twists & turns? Area of mesh?

2. My next step is to redraw the underlay to get all the contours (or at least every other one) with as few nodes as possible. Anyone hit a limit?

3. I don't think creating this with ArchiTerra would make a difference. Am I wrong?

4. Would adding another 1GB of ram make a difference?

Thanks,
Mabe Ng Roche Architect
Cutler-Anderson Architects
Bainbridge Island, WA USA
G5 Dual 2GHZ, 1GB, 128mb ATI Radeon, AC8.1 v2 (2256)

[Anonymous]

My basic question about excessive nodes overloading the mesh is confirmed. I've never had problems working with meshes and prefer splines for magic wanding. The mesh produces polylines but a much smmother model.

It is important to set up the underlay carefully. The original topo.dwg was made up of only several disconnected polylines for each contour. I first connected the polylines for each contour, exploded them (w/ grouping on), then unified the lines (tools:line extras: unify) into one polyline for each contour (w/ grouping suspended.) This was actually quite quick and assured that the magic wand would work properly.

I decided to redraw all of the contours (1 ft intervals) in the area where there will be driveways and grading, using polylines so that the resulting mesh would not add any more nodes. Beyond that area, I added contours only at 5' intervals. I wanted as large a mesh as possible so that 3D images would not show the edge of the mesh. More contours can be added if the area of work expands.

The original mesh is now hidden/locked. Modifications and grading will be made only made to a duplicate. (Difference in volumes is the cut/full.) The new polylines with 90% fewer nodes (which took a couple of hours to draw) will also show on the Site Plan.

~Mabe

[Anonymous]

I've been attaching pdf files which show up as a download, so I'm assuming a jpg will show an image. To verify, I will attach a jpg of the mesh. (Foreground contours are at 1' intervals; distant contours at 5'.)

[Anonymous]

Link,
You wrote:
"I think GS needs to address this issue of magic wanding a mesh to make it easier to create 3D sites. They also need to allow us to select every single line on a site and unify each contour in one go. Who has time to select every single line segment?"
Have you used a program called "PowerCadd"? It has a nifty little
command called "Thin Polygons" that simplfies complex polygons
with excessive points. I had a terrain model where the magic wanding
was slowing to a crawl so I brought all of the polylines into PowerCadd
and simplified them and brought them back into AC and that solved
the problem. Seems to me that the algorythm for the "Simplify Polygon"
command can't be that hard to impliment in AC and would help
when making large complicated meshes. Something for the wish list?
Peter Devlin

[Karl Ottenstein]

Link wrote:
I have posted an image of a site I helped a client/friend of mine with. It's one of the larger sites I have done, and looks similar to the size of yours.

Excellent image, Link! Good example of texture mapping.

Karl