#Boolean Problems
8 messages in this thread
I am having a weird boolean problem with 3dsr3. I am trying to join 4
quadrants of a landscape .dxf file from Vista Pro. Each quadrant is 33,282
faces and overlaps adjacent quadrants by 2 rows of faces (about 60 units out of
total side length of 7,600). Total face count is 133,128 (and this is a
"small" Vista Pro Dem !). All quadrants seem to be properly aligned. When I
choose "Create/Object/Boolean – Union, Weld Vertices" 3ds, after much
computation, simply eliminates the first quadrant selected, as if it were
subtracting instead. "Subraction" and "Intersection" both seem to work fine
and if I use "Union" on smaller objects there is no problem. I have also saved
the model as a .3ds file, exited the program, rebooted and tried again to no
avail. Unfortunately I need the landmass to be one object. What can I do?
Any help would be very greatly appreciated – I'm stuck!
Thanks, John
Your basic problem is that a single 3DS object can't be larger than 64K faces.
– G
I didn't realize there was a limit, thank you. Is that true for r4 as well?
I needed to make the object whole to re-shape it and then massively optimize it
to get the poly count down to a reasonable level for our VR system. Working
with it as a whole seemed to be the most straight forward way to ensure the
object stayed consistant across quadrants and would maintain it's surface
contours as I modified it. I'll come up with another approach.
Thanks again for the info. Cheers, John
>>Is that true for r4 as well?
Yup. We'll be taking that limitation out in the future, fyi.
– G
You could try to welding the vertex together. I had to do this once with Vista
Pro to get the quads right. make shure to smooth the object face after welding
so you do not get black shading lines where the objects meet. BTW I have found
that Displace works well for custom DEMs. Brandon
That is good to know. I have been doing a lot of landscape stuff that are
usually a minimum of 200000 faces. Takes a while to have to split it up into 20
pieces in acad and export to 3ds and all. plus I have to leave it in 64k chunks
in 3ds as well. What was the purpose of this limitation, BTW?
also, the OPTIMIZE routine sure has made life easier since I got it. I've been
running most of my old stuff through it with very pleasing results.
The origins of the 64K/face-per-obj limit comes from 1988, when we were
defining the 3DS data structures while programming in real mode (no Phar Lap
DOS extender yet). Once we got the Phar Lap code in the summer of 1990, the
data structures were so ingrained in the code that we kept putting off the work
it would've taken to change them. We're not putting it off anymore.
– G
I'd use the new Yost Group "optimize" IPAS to reduce the face counts of the
four sections. This routine should be able to reduce the number of faces to
less than 64K, in fact, you might be surprised how few faces will still
represent your land masses. Once the four pieces are reduced (one at a time)
then join them together again and run "optimize" again to re-seam the joints.
(Gary, you know where to send the commission check. 🙂