Importing AutoCAD files to 3ds Max- Best Practices?

[braddewald]

I have wanted to bring up this issue for a while. I generally model in AutoCAD and import the geometry in 3ds Max. I understand that this is a fairly common method. Does anybody here use this as a standard practice? I am wondering if I am importing geometry in the most efficient manner. As I understand it there seems to be a trade-off between quality of curves and leanness of geometry (curve steps, maximum surface deviation for 3d solids). Is this an issue for anybody else? Is there a standard that you use in your import method, i.e. the import screen for dwg files? Also do you have a preferred method of "deriving AutoCAD primitives." Any insight would be very helpful.

 

Thanks,

Brad

[Cad64]

I use Autocad for 2D drafting and Max for 3D modeling, but I do Import my 2D plans to help build the models in Max.

 

I generally set my curve steps to 10 and maximum surface deviation to 0.01. and then Import. If my curves are not smooth enough, I just select the spline geometry and then go to the Modify panel, under Interpolation and bump up the "Steps" until the curves smooth out.

 

I derive Autocad primitives by Layer. This allows me to group similar objects in Autocad onto individual layers, such as concrete, walls, etc. Then, when they are imported, I don't have to spend time breaking out the various pieces to work on.

[Brian Smith]

Check out week 22... http://3dats.com/tutorials.asp

 

Our Intermediate to Advanced book has a much more thorough description of all the different processes, in case you're interested.

[shamsdesigner]

Go to autocad option - Display - Display resolution 250, 10, 10, 10 check this settings...

[Cad64]

Those numbers are Autocad system variable settings that affect the display of curved surfaces in Autocad. They don't mean anything to Max when the dwg is Imported.

 

See my screenshot below. I created a cylinder in Autocad and then Imported it into Max twice. Cylinder 1 was Imported with the Display Settings set to 250, 10, 10, 10. Cylinder 2 was Imported with the Display Settings set to the default of 1000, 8, .5, 4. As you can see, there is no difference when they are imported into Max.

 

You have to adjust your curve steps and max surface deviation on Import in order to smooth out the CAD surfaces.

[TheAllusionisst]

Actually FacetRes controls geometry curve resolution on export and is one solution, but learning to deal with it in Max like others have mention give you flexibility and a solution if the model is provided by someone else. Here is a tutorial on the process as well:

 

http://www.3dallusions.com/forums/tutorials/3458-importing-autocad-models-3d-max.html

[Orbik]

This is how I get around faceted curves from importing.

When importing my 3D model from Autocad (drawn in millimeters) into Max I use the rescale option from the import dialog box in max to convert it into inches. Then once imported I scale it back to mm (3.937% of 100%). this produces smoother curves.

 

When importing to the correct scale (mm) I was getting 4 verts on a 1.5mm rad, Rescaling it to centermeters I got 5 verts and in inches it produced 7 verts and going by logic the larger you go the more verts will be produced and the smoother the curves, but inches works fine for me and is as far as i have gone, you can always put a smooth modifier at a low setting to help, I have found a high smooth setting puts a bit of curve on flat surfaces.

However this does create a lot more polys. Importing in mm my model was just short of 500,000 polys and in inches pushed it over 2,500,000. I am guessing but think If I had drawn this model just in max the poly count would have been around 100,000 mark.

[Rana Mohsin]

Hi, to all

 

It is simple to import dwg file in max.

1. complete your 3d work in autocad and save it as dwg file or with ' w ' command.

2. start 3ds max and then go to import.

3. in Files of type: select Legacy Auto Cad (*.DWG).

4. and then open the file.

5. the curves will smooth,.

.

.

.

[Dave Buckley]

i'm hoping the guy doesn't still have the problem with the thread getting close to 2 years old

[steyin]

I create specific layers when modeling in ACAD, all starting with "3D - ". For curvature, I separate out all curved/rounded elements and export them as a .sat file, then import it separately from the .dwg file.