topic Re: Mesh Tool - Maximum Contours or Nodes? in Modeling

Mesh Tool - Maximum Contours or Nodes?

Anonymous — Thu, 25 May 2023 15:17:30 GMT

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)

Re: Mesh Tool - Maximum Contours or Nodes?

Anonymous — Wed, 21 Apr 2004 05:03:04 GMT

Try ajusting the segment length instead of tolerence under magic wand settings.

Re: Mesh Tool - Maximum Contours or Nodes?

Anonymous — Wed, 21 Apr 2004 07:20:12 GMT

Mabe wrote:
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)

Hi Mabe,
I've done a couple of projects like this one and I've never ran into any problems creating the actual mesh. I have used similar survey drawings (also with zillions of nodes...) and it works fine. I use a relatively weak PC Laptop but that shouldn't make any difference!? So, my answer was worth nothing but I just wanted you to know it shuold work!
:)Mats

Re: Mesh Tool - Maximum Contours or Nodes?

Dwight — Wed, 21 Apr 2004 09:03:36 GMT

Hello Mabe:

Too many nodes: Quick fix - make several segmented meshes that add up to a complete site.

Contour lines being mere interpolations of actual survey data, I suggest not getting bogged-down in giving them too much authority for defining terrain with a mesh. Use fewer nodes placed usefully or reduce drastically you magic wand setting.

I do this manually: Interpolating from no more frquent than ten foot contours by applying mesh nodes or Architerra data points at about 30 foot intervals, frequency is adapted to extremities of slope and detail as needed.

Architerra does make data points easier to enter, creating the mesh only when commanded as data entry is completed.

Additional RAM will probably not help in this case.

Re: Mesh Tool - Maximum Contours or Nodes?

Anonymous — Wed, 21 Apr 2004 16:33:43 GMT

Thanks, Mark, I'd already tried that and I, too, believe it should have worked. (Of course, it hasn't in the past.) I tried several segment lengths, but the new polyline or spline continued to exactly replicate the nodes.

Thanks Dwight,
You have confirmed my suspicions. Thinking it might be a "Mac" issue, it stalled on a PC as well and took too long to generate the 3D view. This mesh is only a third of the total site (golf course, club house, residences) so it looks like it's time to bite the bullet and redraw the contours. Since the contour lines will also appear on the Site Plan, it may as well be done now. I should be able to eliminate at least 90% of the nodes. It was worth a try, and good to know before adding the rest of the site.

Also, thanks for all your tips at ACUW; amazing what a few simple adjustments have done for my 3D views.

~Mabe

Re: Mesh Tool - Maximum Contours or Nodes?

Dwight — Wed, 21 Apr 2004 17:15:54 GMT

You aren't redrawing the contours - you are adaptively interpolating nodes as necessary to depict your terrain. Keep the existing contour lines for plan representation but model the site polygons adaptively. Flat areas need few nodes - complex hillocks need more, but never as many as you think.

Re: Mesh Tool - Maximum Contours or Nodes?

Dwight — Wed, 21 Apr 2004 17:17:03 GMT

that aerial jpeg seems a little rough - it is very smooth in reality....

Re: Mesh Tool - Maximum Contours or Nodes?

Djordje — Wed, 21 Apr 2004 18:01:11 GMT

Mabe wrote:
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.

Just a reminder: the topic of managing survey plans was covered ages ago on the old Talk, and there is a good tutorial on ArchiGuide.

Re: Mesh Tool - Maximum Contours or Nodes?

Dwight — Wed, 21 Apr 2004 18:32:36 GMT

been there done that got the snow dome.

Re: Mesh Tool - Maximum Contours or Nodes?

Link — Wed, 21 Apr 2004 21:20:46 GMT

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.

I have experienced bogging with too many nodes, which kinds makes sense! The key is only showing what you really need (ie. not every single contour!).

Unfortunately there is an inherant flaw when magic wanding a mesh. Magic wanding a mesh (over lines) acts differently than magic wanding a spline (over lines). In the Magic Wand settings, the 'Deviation From Curve' method will place a node at the endpoints of every line, but the 'Segment Length' method won't place nodes at every endpoint, so you will get considerably less nodes in your resulting splines.

However, when we magic wand our the mesh over our splines, AC will add more nodes into the mesh contour than the spline has, ***regardless of the magic wand settings!!*** So sometimes you can end up with more nodes than you would have just magic wanding the original linework!

One advantage to using splines though, is that often the survey lines don't connect properly (which is what it sounds like ~may~ be happening to you) and magic wanding a spline over them will quickly show you where the break is. (Selecting all the contour segments and going to Tools>Line Extras>Unify would also do the trick, but is much more cumbersome).

I think GS needs to addess 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?

Cheers,
Link.

Re: Mesh Tool - Maximum Contours or Nodes?

Anonymous — Wed, 21 Apr 2004 23:56:04 GMT

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

Re: Mesh Tool - Maximum Contours or Nodes?

Anonymous — Thu, 22 Apr 2004 02:29:54 GMT

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'.)

Re: Mesh Tool - Maximum Contours or Nodes?

Anonymous — Thu, 22 Apr 2004 21:38:47 GMT

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

Re: Mesh Tool - Maximum Contours or Nodes?

Karl Ottenstein — Fri, 23 Apr 2004 03:33:23 GMT

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