Exporting Terrain Models for CNC router / physical model fabrication.

[Angelo K]

Hi All,

 

Does anyone have any experience with exporting terrain models to either a .stl or .stp file for 3D printing and/or CNC milling?

 

I have created a simple site model from contours, created Pad modifiers where buildings will be located, and used the hardscapes tool to lay down some curbs (all visible in the attached screenshot). The intention is that this site model base will be CNC milled from a solid block of foam. The contours have been switched on in the display for clarity, but are independent of the model.

 

I have tried exporting both .stl and .stp files. but when I reimport them into a fresh VW file (to check them) they appear either incomplete, or do not at all reflect the model (importing as a jumble of lines).

 

Does anyone have any experience with this and what workflow might allow me to generate a suitable file for milling?

[VIRTUALENVIRONS]

Have you done any 3D printing before this project?

 

[Jeff Prince]

1.Set up your site model for the desired surface character (smooth mesh vs stepped contours, etc).

 

2.From a 3D view, ungroup the site model.

 

3. take the resulting mesh from the ungroup and export it to one or more file types favored by your CNC software.

 

4. adjust the mesh in your CNC software as required to get suitable tool paths.

[VIRTUALENVIRONS]

8 hours ago, Angelo K said:

3D printing and/or CNC milling?

Do you know which one?  They are different processes.

 

[Angelo K]

Thanks @Jeff Prince I have tried this too, but when I export it as an 'untrimmed' .stp and try to reimport it into Vectorworks to see what it might be producing I get a file full of lines (see attached screenshot). When I try checking the 'trimmed' radio box on export it says there are no valid objects to export.

 

And to answer @VIRTUALENVIRONS (thanks too!). No, I have little experience. I work at a Uni with the relevant equipment. I'm simply seeking to establish in the first instance that I have a viable file before approaching people with the relevant equipment. It will be CNC milled on a flat bed CNC mill in the first instance at 1:200 (presumably .stp file?) but I may also want to print a 3D filament model (.stl).

 

I'm more concerned about the former (CNC milling) for now.

[VIRTUALENVIRONS]

Can you post your file please.  We can have a look at it tomorrow.  CNC is top down.  3D printing is bottom up.  

 

 

 

[Angelo K]

@VIRTUALENVIRONS There are a number of experimental layers and source layers in the document but the model is on the 'Base Model working - with hardscapes' layer.

 

Ideally I'd like a file that will recognise the tool pathing to includes the hardscapes (Curbs) too if that's readily possible.

 

Appreciate you having a look at this.

Master Plan Revised.vwx

[VIRTUALENVIRONS]

Hi Angelo,   I think my good friend @Jeff Prince is the best resource for this.  I will look at it tomorrow, but there seems to be an origin problem.  When I convert to group, I get two objects that are miles apart.

 

Have a look, it may solve your problem.

 

 

[Angelo K]

Thanks @VIRTUALENVIRONS. That seemed to help with the terrain part of the model ie. by moving it closer to the origin before export, but I lost the hardscapes due to the model fragmentation when I pasted the ungrouped elements into new layer. Vectorworks seems to have a separate structure for managing 2D versus 3D origins - which I have never really completely understood. My tendency is to never move the 2D origin from the default 3D origin as it causes issues, particularly when working with 3D and trying to align geometry of cartesian X,Y coordinates in 2D to align with those in 3D. ie. I usually assign Z in 3D (corresponding with Y in an elevation) to be the RL (Relative level). Ideally they would align, but if you reset the origin that is no longer the case.

 

When I imported the cadastre for the terrain model - I believe it is to a GIS standard, and therefore a very large world with an origin remote from the modelled item., which doesn't help. I'm also aware that once you move something like a terrain model (as I did to test your suggestion), the underlying geometry used to create it can not longer be sourced to the same X,Y,Z coordinates - which makes drawing things to coordinates (eg a survey) tedious. Not sure how to balance these two positions while facilitating an export for CNC. Any suggestions?

[VIRTUALENVIRONS]

HI Angelo,  Have a look at the enclosed file.  I think this is what you want for CNC machining.  I exported and imported back in as an STL file correctly.

Although I can create site models, I don't use the tools the way you do, except for "Create Site Model from Source", so the terminology is lost on me.

 

ONe layer.vwx

 

[Angelo K]

Apologies for the belated reply. I think the terminology of the AUS/NZ versions may be a little different, but I suspect we are talking about the same thing. It also seems that you need to move the ungrouped model closer to the origin to get the .stl and .stp files to export properly? Although I had better luck creating the .stl file from the reimported .stp file.

 

I have managed to export both successfully. Thanks for your help @VIRTUALENVIRONS.

 

Not sure though that it is CNC ready, as I have been advised for that purpose that there are lots of surface errors that will need repairing. I'll attempt to troubleshoot that next, ideally without any intermediate software following repairs, but if that's something people know about on this forum would welcome any tips.

 

Also, in exporting it to a 3D printing program (as an .stl), while it is coming in as expected, it appears that the model will not print properly because there is no thickness to the model's surface (which Vectorworks creates as a surface mesh). A lot of the model (as represented by the 3D printing software's preview) is support material without any surface. Does anyone have any idea how I can make the model a solid, or at least give it some thickness for the purposes of printing?

[VIRTUALENVIRONS]

13 hours ago, Angelo K said:

as I have been advised for that purpose that there are lots of surface errors that will need repairing.

Surface repair likely means inverted Surface normals, although for CNC they should be able to process them as double sided polygons with the program tessellating the polygons to give a smooth surface.

1-Ask if surface repair means "inverted Surface Normals" 

 

Printing.  Yes, to print something like this you will need a solid thickness.  Optimally It would look like what you get when you first do site q model with the square bottom.

 

Unfortunately, I have reached my "level of incompetence" on this issue.  I seldom use Site model tools.  There may be settings that does this automatically, perhaps someone else will chime in.

 

I will have a look at this again later on in the week.