Boolean problem when subtracting

[ingbertwolter]

When I import a cube from another 3d-application (3DCrafter) and try to subtract a cube generated in 3dsMax I get an incorrect subtraction.  Only the front and back are cut out and I can see into a hollow box. Doing the same with both cubes generated in 3dsMax a correct subtraction (tunnel) is generated. What am I doing wrong?

Images: Test_1: Imported Cube with 2nd cube generated in 3dsMax

             Test_2: Result after Boolean subtraction

             Test_4: First cube (large) and 2nd cube (small) generated in 3dsMax: Correct result

Remark: I am new to 3dsMax, so excuse my question and ignorance...

[Steve_Curley]

Imported box is inside out. Try this as a test:-
Create the big box (in Max), convert to Editable Poly. Select all of its Polygons and Flip them. Create the longer one and do the boolean - same results as in your image.

[ingbertwolter]

I tried it and it worked as you described. But flipping the polygons in my imported cube didn’t make a difference, it’s still not a tunnel. I guess the exporting from 3DCrafter or the importing into 3dsMax screws someting up. I tried an export and import in another format and this time the Boolean was o.k. But unfortumately I lost the materials and the textures exporting in that different format.

[Steve_Curley]

Different file formats have different capabilities. FBX should retain simple materials, many others don't.
Right-click the imported object > Object Properties > Backface Cull (turn it on). Should be obvious if the polys are inside out. If they are, flip them. Do the boolean, if you don't get the tunnel select the 2 Borders (the edges around the 2 holes) and Bridge them.

A bit of a cheat, but...
Export twice, once in a format which works with the boolean, the other in a format which keeps the material. Do the boolean on the one and copy the material from the other. That one can be deleted once the material is copied.

[ingbertwolter]

After several tries, I decided to do all the Booleans in 3DCrafter (which I used so far to do the modelling). There it works without problems. I found out, that exporting the models in .wrl-Format and importing into 3ds Max gives me both worlds, the geometry after Boolean and the original textures. That way, I can use the superior features of 3ds Max like baking and ambient occlusion.

Thanks again for all your feedback and support!

Ingbert

[Steve_Curley]

Glad you found a usable workaround 🙂

[PROH]

Hi ingbertwolter

Just a little sidenote to clear things up. In order to have the Boolean subtraction making a "tunnel", the mesh needs to be a welded watertight mesh. Some file formats breaks the geometry into seperate elements, so that the object no longer is a welded watertight mesh.

In such cases you need to weld all vertices in your object before using the Boolean tools, in order to get the expected result.

Hope it helps 

[ingbertwolter]

Thanks,

I tried it. Before, I ran the STL-Test and it reported errors. After welding it did not. But, sorry to say, it didn’t make difference for the Boolean.

Ingbert

[PROH]

Strange... But then again, Boolean operations I Max always has been quite bad.

Glad you found a workaround 🙂