#Help with Importing DXF
13 messages in this thread
I am trying to import a DXF file created with Autocad R11. When I import my
files clients all I get is objects that are not complete. I have tried all of
the different settings in 3DS R4. Please help.
His file:
True 3D drawing created in Anvil 5000 files. Exported to DXF.
Loaded into Autocad R11. Looks Ok.
Reexports to DXF from Autocad R11.
What I have tried:
Used Autocad R13 from Vendor to import DXF and save to 3ds file.
Same as R4 gave me.
Used DXF3DS stand alone file. Nothing New.
Has anyone had success exporting DXF to 3DS? Please respond ASAP. Our deadline
for this projects is approaching fast.
Bob G.
Bob:
Could be that its all there but the normals are pointing in different
directions. To check this out just render a scene with FORCE TWO SIDED ON.
Another possibility is that you've imported the model with automatic vertice
welding on. Try this one without that function. That's all I can think of for
now. Let me know if it works.
Bob
It sounds like the model was not biuilt correctly for a polygon renderer
(the MOST common problem in not getting models in properly to 3DS via DXF).
If your model is composed extensively of individual entities (3D Faces or
Lines with thickness) then you are probably experiencing this problem.
There is one golden rule when constructing such entities in _any_ program:
every face that's adjacent to another face (that is of the same mesh) must
share two vertices with it. If this does not occur, and only one vertex is
shared, then the face normal is going to be erratic.
While it may be too late to correctly model this pproject, keep it in mind
for your next. Until then, you'll have to resort to rendering a LOT more
faces by using the 2-Sided opotion as Robert suggested. Remember, don't try
using Boolean operations or SXP materials on this model since they will not
work correctly.
– Phil
p.s. (check out chapter 11 of "Inside 3D Studio" for an extensive discussion
of DXF import into 3DS).
I've had problems with importing DXF files where most of the geometry was done
with AME solids. I had a lot of missing faces – not just flipped normals but
entire faces gone.
Mostly I have been building things like a set of complex internal walls for a
building with doorways cut into it, etc.
Chris
– Chris Johnston, Written 11-Jan-1995 @ 00:03:05
Using: Windows NavCIS PRO 1.25
AME models _should_ have correctly faced & welded normals. You may want to try
importing them with the Unify Normals and Weld Vertices options OFF.
– Phil
Phil: I had started to play with import settings but the DXF file I was working
with was about 32 MB long and I needed to (and still do!) get the model ready
to render so I dodn't play with it as much as I would like to, Once I get this
animation done, I'll probably play with importing a simpler model to see how
things change. I just upgrades to Autocad R13, so I'll probably end up doing a
lot of experimentation anyway.
My major reason for using Autocad as a modeler on complex models is because
boolean operations seem a lot more reliable and I can use multiple objects with
them and I like Acad's ability to input relative coordinates.
I like the 3DS modeler a lot so I tend to use Acad only for complex models.
Chris
– Chris Johnston, Written 12-Jan-1995 @ 21:03:34
Using: Windows NavCIS PRO 1.25
You could try DXF'ing a large file out in pieces, if you wanted. Also, you can
"merge" (create/object/join) entities in 3DS prior to any boolean operations,
I've found that this actually works better than doing a series of boolean
operations…
Gary: Yes, I've thought of exporting the DXF in pieces. I'm too far along in
the current project to try that now, but I'll probably try it when I get done.
I have tried joining objects and then doing a boolean, but it dosen't seem to
impact on the tendency of 3DS to start a boolean operation and then give up
after advising me to adjust the geometry. Autocad seems to always be able to
complete a boolean subtract.
Chris
– Chris Johnston, Written 14-Jan-1995 @ 20:44:38
Using: Windows NavCIS PRO 1.25
>>attach, then boolean…
PMJI, but one major thing to remember with booleans in 3DS is that you often
cannot complete a boolean in an area where two (or more) elements overlap on
one of the objects. In this case, it is usually possible to detach the two
elements, boolean UNION them together, then retry the failed boolean operation.
I agree with the difference you noted between 3DS and Autocad booleans. I
think the difference is that 3DS is working with a multitude of individual
faces, while Autocad is working with mathematical descriptions of the component
primitives.
JKJ
One thing that I've had to do on a number of occasions is to Boolean subtract
out holes for windows in a wall. That is where I've tried joining all of the
window hole objects into one object and then subtracting it from the wall.
The other is that I've had a model that I used in another animation that I
needed in cross section for the current project. In Autocad I could use one
subtraction object and do all of the booleans at once. In 3DS I have to make a
series of duplicate objects and boolean one thing at a time.
Chris
– Chris Johnston, Written 17-Jan-1995 @ 21:21:04
Using: Windows NavCIS PRO 1.25
Hi Chris,
Sorry, I'm jumping in late for this one, but I'm experiencing the same problems
at the moment.
I had a 25MB DXF-File with 2 Layers more than 64K Faces, and had a lot of
trouble with it.
I noticed, that I got different translations with different methods.
I started with converting the whole file – what, of course, failed after 6
hours converting : "not enough ram ". I upgraded memory (got enough in my
company<g>) – same result.
After crying for help, Gary (Yost) told me, this message is due to the 64K Face
restriction…..
Ok, I splitted the whole damned thing to multiple wblocks, converted them to
dxf – and got a relatively
good copy of my objects, of course some were missing (even though they were
made out of 3d-Faces…)
<AAARGH!> first time to get tempted to throw everything from my balcony !
Then one nice guy sent me a lsp-file to convert every single layer to a single
dxf-file. (uploaded it to utilities)
– Did it, converted 40 files to 3ds, merged it. Got another fine model with
different elements missing. (PLEASE, don't ask me why).
Next thing I'll do is deleting the two big layers (unnessecary plants) and
shoot it through the dxfto3ds utility that's on this forum.
Then I'll start to combine all parts into a heck of a mesh………
You see it's a tedious work – From now on I tell all my clients to do the
following:
– Split layers up if there are more than 64000 Faces on it.
– Put only parts with the same material on one layer (speeds up mat-assigning)
– If there are 2D Polylines that need to be lofted (had this with a swimming
pool now) put them on separate layers
If they don't agree to this – I multiply my fee with two (AND TELL this to MY
CLIENT)
– else, nobody's gonna pay for my wasted time.
I don't know if this helps, but for me it's good to know that I'm not alone
with those problems.
Bye and good luck
Michael
Michael: I don't think that I had the 64K face problem. I had a lot of objects
but they were on a lot of layers. I ended up getting all of the objects, but
many of them had faces missing – a lot of one-sided walls, for instance.
Chris
– Chris Johnston, Written 21-Jan-1995 @ 22:40:22
Using: Windows NavCIS PRO 1.25
The best way to get a DXF to 3DS file is to use the new 3DSOUT command in
AutoCAD Release 13.
You then get a beautiful 3DS file ready for use!