topic Re: AutoCAD 3D Commands in AutoCAD Forum

AutoCAD 3D Commands

kcol-kkc — Fri, 17 Mar 2017 21:50:11 GMT

I am teaching myself 3D design in AutoCAD Civil 3D 2017. Civil 3D is what's available to me so that's what I'm using.

I have been creating shapes and then using the STLOUT command to export it as an .stl file.

I then load the .stl file into Slic3r to prepare it for printing on a 3D printer. I have been having a huge amount of difficulty with this. Finally I have discovered that the object I open in the .stl file is only 1mm high. I drew it over an inch high.

So why is my object. Drawn at a 1:1 (I think) in AutoCAD. Being squeezed down to 1 mm in thickness? My Units? Scale?

Any help would be greatly appreciated.

Also it's the end of my day and the end of my workweek so I won't be checking this until Monday.

Thanks in advance for the help.

Re: AutoCAD 3D Commands

john.vellek — Fri, 17 Mar 2017 22:00:43 GMT

Hi @kcol-kkc,

Can you share the model? I would like to try exporting it to an STL and then look at it in Inventor or Fusion 360 to verify the dimensions are correct.

Please select the Accept as Solution button if my post solves your issue or answers your question.

Re: AutoCAD 3D Commands

kcol-kkc — Fri, 17 Mar 2017 22:04:49 GMT

Absolutely.

Re: AutoCAD 3D Commands

Anonymous — Fri, 17 Mar 2017 22:44:42 GMT

Model looks ok, settings appear right unless i've overlooked something, did a round trip through STL to DXF and back in DWG and got back what I sent to STL. (I did UNION the solids into one solid first, cuts down on "seams" in the final product.

I'd say there is a unit setting at the 3dprinter side that is set to mm instead INCHES.

Re: AutoCAD 3D Commands

Alfred.NESWADBA — Fri, 17 Mar 2017 22:50:36 GMT

Hi,

an STL file does not know "units", it exports the value as it is - as number without a unit definition.

How that number is interpreted (as Inch or Millimeter in most cases) is part if your slicer software. Or you have to use your slicer software to scale the model before printing.

- alfred -

Re: AutoCAD 3D Commands

john.vellek — Fri, 17 Mar 2017 22:57:40 GMT

Hi @kcol-kkc,

I changed your units using -dwgunits to Inches instead of feet. Then, I ran surfsculpt to get everything into a single solid. I was able to export the STL and open in Inventor and it measured correctly. I also brought it into Fusion 360 to verify that it looked good.

I next took the model into PrintStudio and added supports and everything looks good.

So, I suspect that you need to revisit your print process as this seems to work great on my side.

Please select the Accept as Solution button if my post solves your issue or answers your question.

Re: AutoCAD 3D Commands

Alfred.NESWADBA — Sat, 18 Mar 2017 01:06:29 GMT

Hi,

>>I changed your units using -dwgunits to Inches instead of feet

Look to >>>this description<<< (or others), a STL-file does not contain any information about units.

The only thing you can do with -DWGUNITS is to scale the objects, then the result is that the objects are larger or smaller (but only the values you get by "_DIST", independent of units). That gives also another result in any STL-viewer looks larger or smaller. But again: indenpendent of units-setting in AutoCAD.

You can set the AutoCAD units to Angstroms or Lightyears, it does not change anything for the exported STL 😉

- alfred -

Re: AutoCAD 3D Commands

kcol-kkc — Mon, 20 Mar 2017 14:23:26 GMT

Alfred hit it square on the head. The units in the STL file are just numbers. My Slic3r was reading the units a mm. But my AutoCAD was drafting them as inches. I... assumed if drawn in inches they'd come into Slic3r as inches. Wrong assumption. I have not had any success switching Slic3r over to imperial units so instead I have scaled my drawing up 25.4 and the .stl file comes into Slic3r at the correct size.

I hope I explained that correctly. The issue is not AutoCAD it's my slicer software.

Re: AutoCAD 3D Commands

kcol-kkc — Mon, 20 Mar 2017 14:26:45 GMT

John,

The supports you drew are impressive. That is the next hurdle for me to get over is supports and understanding when and how to use them. Is this PrintStudio an Autodesk product?

Re: AutoCAD 3D Commands

john.vellek — Mon, 20 Mar 2017 21:54:15 GMT

Hi @kcol-kkc,

I set the units in my file as decribed earlier from feet to inches because I tried a variety of exports and didn't want to play with scaling. I know that the IGES file I created and brought into Fusion 360 worked very well. I then "Printed" to PrintStudio which is an Autodesk product. It allowed me to auto-scale, auto-orient, check for errors and then easily add the supports.

Please select the Accept as Solution button if my post solves your issue or answers your question.