Convert .dwg to .stp

[dkm2112]

I am running Inventor 2020 and True View 2021.  I have read through many threads and have been unable to convert the attached 3D .dwg to a .stp file.  It's either grayed out export options or processing errors like others have seen and I have followed multiple steps and options.   I would appreciate any help with the process.  

Thanks

[JDMather]

How far is was the geometry from the Origin?

See Attached file.

[j.palmeL29YX]

here it seems to work. See attachment

[JDMather]

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@j.palmeL29YX wrote:

here it seems to work. See attachment

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Are the units and size correct?

[dkm2112]

Thank you for sending the file along. At this point, the .stp file does appear to be correct. It is quite far from a 0,0 origin point but can be moved if need be. I have several .dwg files that will need to be converted. What is the actual process? I have followed various versions with no success.
I appreciate the help.

[dkm2112]

Thank you for sending the file along.  At this point, the .stp file does appear to be correct.  It is quite far from a 0,0 origin point but can be moved if need be.  I have several .dwg files that will need to be converted.  What is the actual process?  I have followed various versions with no success.

I appreciate the help.

[JDMather]

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@dkm2112 wrote:

 At this point, the .stp file does appear to be correct. 

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I didn't post a *.stp file.

Is the *.stp file that @j.palmeL29YX  posted the correct units and size?

I saw 240ft across one side in AutoCAD if I recall correctly (I only checked one side).

I cannot explain the steps without verification of units and size, especially since I see conflicting information  between the results given here.

(I just double checked and I get 240.1'x162.1')

[dkm2112]

Good question and sorry about the confusion. Once a verify the output size, I will respond.
I really appreciate the help.

[mcgyvr]

@dkm2112  Do you have access to Autocad?

I exported to STL in Autocad and opened that in Inventor quite easily.. 

[j.palmeL29YX]

I did it a similar way as @mcgyvr: In AutoCAD export as .sat file, in Inventor open the .sat file and save as .stp. Perhaps you must additional scale the model (1:25.4) - I did'n check it (sorry).

[dkm2112]

So, after following the .sat to .stp process it does appear to work.  This particular tile is 162 x 240mm and will be part of a larger terrain model.  The next issue appears to be refinement and we have had this problem when we have created .stl files in other ways before using Inventor.  The original cad file has straight outer edges so that the tiles placed next to each other should fit perfectly.  During the conversion to .stl the jagged outer edges appear as seen in the attached image.  Is there a refinement somewhere in the process that I am missing?

Thanks for all the help

[JDMather]

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@dkm2112 wrote:

  During the conversion to .stl ...

I opened the DWG file directly in Inventor.

I did not convert to ACIS (*.sat).

Why are you converting to stl (an inferior format).

Can you explain your entire design intent?

[dkm2112]

The task at hand is take a terrain model created in Autocad , split it and print multiple rectangular tiles since the entire model may end up being 3'x5'. The cad file I sent is one of many parts in the grid. When I open the .dwg tiles in Autocad the outer edges appear to be perfectly straight. If I open the same .dwg in Inventor, those same edges appear to jagged as in the previously attached image. When the actual tiles are printed and placed together the edges of course don't match up which led me to the conclusion that there was something I was missing in a conversion somewhere. Probably the incorrect conclusion! I was having trouble in the beginning just going straight from .dwg to exporting to .stp in Inventor due to grayed out export commands.
To sum it up, I need the original .dwg to be printable with straight outer edges which it appears to have in its original format. I didn't realize .stl was inferior so that's useful information!

[JDMather]

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@dkm2112 wrote:
The task at hand is take a terrain model created in Autocad , split it and print multiple rectangular tiles since 

...to exporting to .stp in Inventor 

To sum it up, I need the original .dwg to be printable with straight outer edges which it appears to have in its original format. I 

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Why are you going from AutoCAD to Inventor just to 3D print geometry.

Why are you going to STEP (*.stp) to 3D print geometry?

It sounds to me like you are going through a bunch of unnecessary translations (and probably introducing issues).

All 3D printers that I am aware of use stl files, not STEP.  So why do you need STEP?

The terrain is obviously stl triangular faceted planar faces.  It is what it is. 

AutoCAD will ouput stl for printer directly (stlout is the command).  So why wash through Inventor STEP?

(Set facetres to a high value for resolution before stlout.)

BTW - it is visually obvious that stl is an inferior geometry format.  Simply create a sphere and save in stl format.

Open the stl file. What do you observe (Answer: Thousands of triangular planar facets rather than smooth spherical curve.  Straight lines and planar faces, sphere is gone.)

[dkm2112]

We initially used Civil 3d but there was no control over resolution in the .stl export.
We next looked at Autocad export to .stl but the facetres refinement setting does not seem to have any affect on the output resolution no matter what the value is set to.
This is when we started to grasp and look at alternative methods and workarounds because when viewing the original cad file, the outer edges certainly appear to straight. I have viewed in 3D and plan view from the bottom and drawn polylines from corner to corner and it appears to be a perfect rectangle initially and then in translation it's possible having trouble with the faces and it's not able to slice in a straight line.
When printed, the adjacent tiles do not match up due to the jagged edges.
Thanks

[JDMather]

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@dkm2112 wrote:
We initially used Civil 3d but there was no control over resolution in the .stl export.
When printed, the adjacent tiles do not match up due to the jagged edges.

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Given that Civil3D is built on top of AutoCAD I would expect the same Facetres and stlout commands to work.

But you will not get a better output than the original source.

I think there are smoothing tools in Civil3D for the contours (you should be posting this in that user forum).

I would want this converted before splitting up the tiles (but there might be too many faces).

When the stl is made after tiling - the sides may not remain planar.

This could be edited in MeshMixer, but again, iffy results getting better results than the input geometry.

The sides could be replaced in Inventor with planar sides, but a lot of work.

How much discussion have you had in the Civil 3D forum?  I would expect the real solution to occur at the source.

Here is the same sphere with stlout at two different facetres resolutions in AutoCAD. (But this is conversion of sphere to planar facets.  My guess in that your Civil 3D geometry was always planar facets (no curves). But I have no experience with Civil 3D.)  The key is the input will be better than the output.  The output will never be better than the input.

I recommend that run over to the Civil 3D forum and start asking questions.  You might have to be persistent till you find someone with the right experience.  

If that proves to be a fruitless endeavor, I can demonstrate how to get planar sides on these tiles, but it will be work (which I try to avoid).

Edit:  Didn't I see somewhere in later releases of Inventor a tool to replace planar facets with a single face?

Edit2:  Wait a minute, the file that I posted earlier has planar sides???

[JDMather]

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@dkm2112 wrote:
When printed, the adjacent tiles do not match up due to the jagged edges.

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OK, let's back up to the beginning.

Attach the file here that you are printing that results in jagged edges.

I think I know where the problem is now.

[dkm2112]

Here is an original.

[JDMather]

That is a dwg file, not a stl file?

How are you 3D Printing dwg file?

Are you printing these in-house or sending to an outside vendor for printing?

[dkm2112]

Here are 2 .stl files that I just created from Autocad stloutput using both extremes for the facetres resolution setting. When I view these in a slicer you can immediately see the edges as jagged.  We then convert to gcode but the problem appears before we even get to that point.