Can a STEP file import into MoI with materials assigned?

My client has given me two file formats of a ProE model: OBJ and STEP. When I import the OBJ into Cinema 4D using Riptide, I have the mesh split by materials. Materials that the engineer assigned carry over to C4D.

I’m wondering if there is a way for the same materials to be assigned when I import the STEP file into MoI. Does STEP format support this?

Thanks for any help!

–Randy Geske

Hi Randy,

> Does STEP format support this?

The STEP format itself has some support for colors, but unfortunately the STEP import library that MoI uses does not currently know how to read them in yet.

I think this is something that will be able to be fixed up in the future. For now you could try using some other CAD program to go from STEP to 3DM format, like for example if you load the STEP file into Rhino and save out from Rhino as 3DM, then load the 3DM into MoI may be a way to get the colors preserved.

- Michael

CAD applications in general don't transfer textures/materials well, or at all.

I wish there were standardized procedural textures and texture mapping, but it would probably have to come with a new 3D cad format. I don't know if there is "room" in any of the current formats like IGS, STP, SAT etc. to incorporate this.

DarkTree http://www.darksim.com/html/products.html http://www.darksim.com/Repository/index.html started to do this with procedural textures and poly modelers but unfortunately it never really caught on. I think it was a very good idea.


Michael,

I thought OBJ had support for nurbs surfaces (or at least spline surfaces) but I have never come across any applications that write nurbs/spline surfaces to OBJ files.

Do you have any idea why developers don't use this function?


Chris

Hi Chris,

> I thought OBJ had support for nurbs surfaces (or at
> least spline surfaces) but I have never come across any
> applications that write nurbs/spline surfaces to OBJ files.
>
> Do you have any idea why developers don't use this function?

It's basically a chicken & egg problem - most programs don't write NURBS data to OBJ files because there aren't many programs that read NURBS data from OBJ files. And most programs don't read NURBS data from OBJ files because there aren't many programs that write NURBS data to OBJ files.

Rhino does have an option to write a NURBS OBJ file, but as far as I can tell it is rarely used. I think PolyTrans is another application that can read NURBS OBJ.


A lot of programs that use OBJ format are polygon based programs that don't use any NURBS functions themselves, so that's another reason.


- Michael

Hi Chris,

> I don't know if there is "room" in any of the current formats
> like IGS, STP, SAT etc. to incorporate this.

Not really - although there is some room for sticking in custom data into some of these formats you would need to get a lot of CAD vendors to agree how to treat the custom data all in the same way for it to actually work for data transfer.

That's a pretty tall order because it is difficult enough just getting everyone to handle data that is part of the official spec as it is.

- Michael

Michael, thanks! I have a demo version of Rhino with a few saves left, so I did as you said.

The STEP file imported into Rhino okay and I saved out a 3DM file. When I opened up the file in MoI there was nothing in it.

Also, I don’t know Rhino much at all, but I couldn’t find any material or color assignments anywhere. Should I assume that color information isn’t being preserved?

–Randy

Hi Randy - hmm one issue that I forgot about is that Rhino may tend to make block instances out of stuff it reads in from STEP files.

MoI doesn't read in blocks, so if that was the problem try running the "Explode" command in Rhino before saving, that will convert any blocks into just regular geometry that MoI should then be able to see.

You can see what type of object it is in Rhino by selecting something and running the "What" command, and if it says that it's a block instance then it needs to be exploded.


> Also, I don’t know Rhino much at all, but I couldn’t find
> any material or color assignments anywhere. Should I assume
> that color information isn’t being preserved?

Yeah if you don't actually see the colors in Rhino then they didn't come into Rhino either - you would probably normally see them as layer assignments with the layer colors set up.

It could even be possible that Pro/E does not write out color information to the STEP file in the first place.

- Michael