Exporting to .dwg and .dxf. - curves?


#1

Looking for an education on the subject of exporting for autocad. Is there anyway to retain circles and curves, rather than have them just show up as segments?


#2

Simple answer would be: No.

I have not come across any method to do so.

Are you trying to manipulate them in different program?


#3

Trying to generate CNC toolpaths


#4

if you increase the segment count of the curve, they would be fine in my opinion.

I think other woodworkers may have different idea or solution.


#5

Use the Export as a 3d Model option and it will export true circles and arcs.


Exporting dwg files to engineer
#6

Here is where I’m at:
I don’t own a copy of any autodesk product.
I am using sketch up to generate geometry (curves, mostly, plus circles and a few lines) for a set of forms and jigs for building a guitar body.
Any file manipulation in AutoCAD I pay $85/hr for, while sketch up time (mine) is free.

As it stands, the document I exported needs to be extrapolated from to redefine every circle and Bézier curve. Elevating the segment count on the curved entities won’t change the basic fact that the AutoCAD guy will need to extrapolate continuous geometry from the segmented geometry.

Does this assumption sound right?
Thanks


#7

There is a difference between 2d and 3d DWG/DXF Exports.
The 3d Export includes Arcs, Circles etc as those equivalent CAD things - i.e. smooth ‘curves’ without segmentation.
But the Export as 2d always makes everything out of Lines - and irrespective of the SKP’s Circle’s segment count in the 2d CAD version it has 24s…


Exporting dwg files to engineer
#8

on my mac a 64s SU arc exports as 64 edges with dxf 2D export?

@bevanfrost do you use the Pro version?

john


#9

For the next 3 weeks.
I intend to do all my drafting (3 more instrument models) and exporting before then


#10

@john_drivenupthewall

You are correct. :blush:
Brain-fart…
The Circle’s increased segmentation on export is retained in the 2d CAD file as more/shorter Lines.
What I was thinking of was that the import of CAD data always converts CAD-Circles into SketchUp Circles with 24 segments etc…


CAD/DWG import option
#11

Thanks for all the help,
3d exportation has solved my problem.
This community makes this tool easy to use. Thanks so much.
Bevan


#12

if you wanna check the generated DWG/DXF data, you may want use either the free Autodesk TrueView (actually a stripped off AutoCAD) or the also free but much smaller ODA Teigha Viewer also available for Mac OS X v10.8+ (and Linux/Android).


#13

The good thing about TrueView is that it can also show what is in the Paper space tabs, and that it can translate the latest DWG format down into older version DWG or DXF files (way back to the days of DOS versions, I think).

Anssi


#14

Try this… When you first open Sketchup, create a circle of any size, and then type 96s. Watch this video:

From this point forward, within this file, all your circles should automatically have 96 sides. Now when you export, your CAD/CAM program has enough information, that your intent is to have an even circle. It works in BobCad, and I suspect it will work in other CAD programs as well.


#15

As said earlier in this thread, there is no need to worry about the segments if you use the “3D Model” option to export to DWG or DXF. The circle or arc will export as a circle or arc, with no segments involved.

Anssi


Exporting dwg files to engineer
#16

[quote=“Anssi, post:13, topic:16066, full:true”]
…show what is in the Paper space tabs, and that it can translate the latest DWG format down into older version DWG or DXF files…[/quote]

Teigha does support paper spaces and saving to older versions (DWG r12 / DXF r9) too.