topic Re: Autocad drawings coming in at the wrong scale in Fusion Support Forum

Autocad drawings coming in at the wrong scale

Anonymous — Wed, 04 Aug 2021 08:41:37 GMT

I recently switched from Autocad 2002 to fusion360 and I'm having problems importing DWG files. they are coming in at different scales. They were drawn in mm and 360 is set for mm yet the imported files open much larger. What am I doing wrong?

Re: Autocad drawings coming in at the wrong scale

HughesTooling — Wed, 04 Aug 2021 09:01:12 GMT

Fusion usually does a good job reading the unit info. Have you got a sample DWG file you can share? You might need to zip the file to attach it.

Thanks Mark

Re: Autocad drawings coming in at the wrong scale

Anonymous — Wed, 04 Aug 2021 13:44:39 GMT

I have attached the latest file I have opened. it has come out about 10x bigger than it should.

Re: Autocad drawings coming in at the wrong scale

Anonymous — Wed, 04 Aug 2021 13:57:07 GMT

I have just opened the drawing again and one part is the correct scale and the other isn't. Not sure what is going on!

Marc

Re: Autocad drawings coming in at the wrong scale

TheCADWhisperer — Wed, 04 Aug 2021 14:01:32 GMT

-dwgunits indicates that the AutoCAD was done in Inches (actually back in 2002 AutoCAD was Unitless).

If you have access to AutoCAD run the -dwgunits command to convert to mm units.

Re: Autocad drawings coming in at the wrong scale

HughesTooling — Wed, 04 Aug 2021 14:01:38 GMT

When I open the file with ZW3D it lists the units as Inches. I don't have AutoCAD to double check, @TheCADWhisperer might be able to help.

Size imported into Zw3d and Fusion are the same 26.864 inches or 682.337 mm

Re: Autocad drawings coming in at the wrong scale

HughesTooling — Wed, 04 Aug 2021 14:07:45 GMT

Just noticed Fusion seems to be positioning some part differently. Rhino on the left Fusion right, not sure which is correct.

Re: Autocad drawings coming in at the wrong scale

Anonymous — Wed, 04 Aug 2021 14:08:09 GMT

that would explain things.

Re: Autocad drawings coming in at the wrong scale

HughesTooling — Wed, 04 Aug 2021 14:11:44 GMT

Also notice the part on the right is a different size in Fusion. Not sure what's going on there.

Re: Autocad drawings coming in at the wrong scale

Anonymous — Wed, 04 Aug 2021 14:12:32 GMT

The part should be 26.66mm not 26.66 inches. I only have access to AUTOCAD LT2002 on a very old laptop.

Marc

Re: Autocad drawings coming in at the wrong scale

HughesTooling — Wed, 04 Aug 2021 14:17:36 GMT

@TheCADWhisperer Didn't you used to be able to set the INSUNITS even in older versions of AutoCAD so files used as blocks had their units set? Seem to remember setting this in AutoCAD Lt years ago.

Thanks Mark

Re: Autocad drawings coming in at the wrong scale

TheCADWhisperer — Wed, 04 Aug 2021 14:26:51 GMT

@HughesTooling wrote:
@TheCADWhisperer Didn't you used to be able to set the INSUNITS even in older versions of AutoCAD so files used as blocks had their units set?

INSUNITS does not do what most people think - it does not set units (there was no unit information in the dwg format set, kind of like stl now) - it merely scales geometry.

AutoCAD was unitless years ago, INSUNITS was simply SCALE set to apply appropriate scale factor depending on what the user selected as their intended "units".

@Anonymous

Since you don't have a newer version of AutoCAD - you will have to scale your sketch in Fusion.

I would double and triple check everything (dimension and fully define) after scaling as I saw some questionable stuff in the AutoCAD dwg file. Don't trust it as is.

Re: Autocad drawings coming in at the wrong scale

HughesTooling — Wed, 04 Aug 2021 14:25:42 GMT

@Anonymous Can you save as a DXF instead then use Insert DXF in Fusion and override the units to mm on import. Insert DXF is on the insert menu.

Re: Autocad drawings coming in at the wrong scale

Anonymous — Wed, 04 Aug 2021 14:27:58 GMT

I'm starting to wonder if it would be quicker to start from scratch

Re: Autocad drawings coming in at the wrong scale

Anonymous — Wed, 04 Aug 2021 14:33:12 GMT

I will give the dxf route a try nothing lost.

Re: Autocad drawings coming in at the wrong scale

Anonymous — Fri, 06 Aug 2021 08:36:17 GMT

I tried the dxf route same result. In autocad the to drawings are sat on top of each other. so in the import it has moved one part and rescaled both bits. I have given up and started again.