#Goverment Job
10 messages in this thread
My boss has some property in southern Ohio and I made him a 3d Topo map with
extrude polylines in AME. This creates a stepped model and took all day to
create. He wants a smooth model now, bless his heart. Whats the best technique
for this. Is their some software that will generate the model.
Merry Christmas
Max,
Schrieber has a 3d surf program which supposedly works great as an
ipas in 3D Studio. Will generate terrain from autocad data. If you
are not working from a file, it will randomluy generate hills. Sounds
like you might want the autocad add on Landcadd
Rick
I'll check out Landcadd
thanks
max
Max,
Let me know how it works. I may send some contract work your way.
Rick
Max:
We use Schreiber's QuickSurf ACAD add-in for all our topo needs, has worked
well for years!
Greg Pyros
Hi Greg,
PMJI… I have the DEM Data CDROMS in USGS 3" format. I find when I bring a
topo in that the vertical data is often not true to the live landscape it
represents. Any chance you could do a test for me and tell me how a particular
land feature comes out using Quicksurf? How about Devils Tower, Wyoming as a
test? Coords 104.7-104.9 44.6-44.8.
Bill.
Bill:
I'd be happy to take a look at it, depending on how soon you need it! <g> Even
better might be to send it to Chris Thomas [71031,3133] from Schreiber, who
would be happy to test it out for you with QuickSurf and/or 3D Surf to see
which would be better for your application!
Let me know! Happy New Year!
Greg Pyros
>>3D topo map to mesh…
Do you want an easy way or a free way? If I had to do more than one, I'd
definately look into one of the add-on's for Autocad.
If you've got more time than money for new software, you can do it
with 3DS. I made an effective mesh from topo data not long ago using
a method I made up as I went. The method is a little convoluted to
describe in words, but if you're interested…
-Create curves for each elevation line in the shaper. (I actually
scanned the map and manually traced the lines in CorelDraw,
exporting as .AI)
-Duplicate all lines and move the dupes out of the way (with SNAP!)
for now.
-Connect each contour line with an adjacent contour line at the
edges of the map to create a series of closed shapes, with spaces
between them.
-With the duplicate made earlier, connect the contour lines again,
but this time connect the pairs of lines such that what were spaces
in the first set are now closed shapes in the duplicate set, etc.
(Sort of the inverse of the first set.)
-Select all the first set of shapes and loft or GetShape.
-Select the second set and loft or GetShape, realigning them
precisely. You should now have two objects, each filling in the
"holes" left by the other.
-Attach the two objects. Select all the vertices and weld. If
lofted, detach the ground surface faces.
-Now, the easy part <g>: one level at a time select all the vertices
(by fence) for each discrete contour level, and /Vertex/Move
"Selected" in a side view some distance vertically. For example,
with an elevation range from 720-745 in steps of 5 ft, move the
725 line up 5 ft, etc.
-Smooth 100% and edit as necessary. I found a little thoughtful
application of Modify/Edge/Divide and Turn would fix those few faces
that appeared unsmooth when rendered.
This method worked very well and gave me an accurate mesh.
I'm definately not saying this is the best way, but is certainly is
cheap enough for a "government job". For about $150 you can get
3DSURF, but you'll have to create an ASCII file of coordinate data. I
think about $1000 will get QUICKSURF which is supposed to work with
Autocad to make this easy, but I don't have that one. And there are
lots of professional software packages for big buck$ that work with
surface data.
Oh, there's another cheap and dirty manual technique if you've got the
time: with a pencil <gasp!> draw a grid over the topo at whatever
resolution you choose, and create a file containing a rectangular
array of z-values, interpolated at each grid intersection point. I
wrote and uploaded a program (MATHDX.ZIP) which will convert such an
array into a surface mesh.
That's all I can think of just now. Good luck!
JKJ
I started with Corel photopaint and scaned in the map. Lines were to broken for
Corel Trace to connect, I used Acad rasterin command to import a PCX file. It
was huge so I traced them with closed polylines. If I can import those Plines
to the shaper can I use your technique?
max
I've never been happy with any autotrace program I've tried, so I
always end up tracing by hand, ususally in CorelDraw, or right in the
shaper if I only have a few lines. Also, I have very little
experience with importing PLines – most of my Autocad exports have
been DXFs of AME objects. But regardless of how you get the data
into the shaper, the technique I described will work (it is actually
easier than what it may have sounded like, but very time consuming,
depending on how picky you are.)
Also, I have the 3DSURF program here, which accepts an ascii file of
x,y,z triplets. If you can extract that data from Autocad, I could
try running it thru 3DSURF to make the mesh.