Geometry in PDF has wrong dimensions, how to export to Corel Draw?

Serengeti (Rhino WIP)
1

We need to get something laser engraved. The software that the engraver uses is Corel Draw. The last time there were issues with hatches when he imported our DXF files. So we want to try with PDF now.

Here’s where I run into a problem:

  • I create a 1000 mm diameter circle: circle.3dm (26.4 KB)

  • I export a 1000 mm diameter circle to PDF, with 1:1 scale: circle.pdf (2.9 KB)

  • I import the PDF back into Rhino. Now the circle has a diameter of 988.494 mm. Wrong!

How do we create a file that is easy to import into Corel draw, that preserves dimensions and hatches?

I am thinking about using a more modern version of DXF. In the past, I used 12 Natural.

I’m using: BETA (6.0.18012.13241, 2018-01-12)

2

I just tried this with the current 6.1 version. I get a “circle” that is 1000.002 units according to its bounding box. Unfortunately, it is no longer a circle, it’s a polycurve with 24 segments - I do not know if PDF actually supports circle entities - and it will not simplify to a circle under file tolerances, as it is .02mm out according to CurveDeviation.

I would not rely on PDF for accurate vector exports, DXF is the standard, I might also try IGES if Corel imports it. I would try DXF 2004 Natural…

CircleMsh.pdf (1.4 KB)

–Mitch

3

@Helvetosaur Thanks for the suggestions! I don’t have Corel Draw here, so cannot test it. May try with a trial version later.

4

Just upgraded, so we’re on the same version now. And I installed the trial version of Corel Draw.

IGES is not supported.

I also tried AI, and in Corel draw a lot more control points show up for the circle. I now tried again with DXF, in different variations, and with a test file that contains a hatch:

In Corel Draw the hatch is completely off:

corel
corel1600×870 57 KB

rhino-viewport
rhino-viewport1205×690 5.97 KB

5

Just tested: If I add another hatch, then it shows up in the correct position when imported into Corel Draw.

What’s wrong with the hatch that gets misplaced?

6

I guess the question might be “What’s wrong with Corel Draw?” It was supplied when we acquired our first laser more than 10 years ago and it went into the trash can almost immediately…

–Mitch

7

If I redraw the hatch in test.3dm (595.4 KB), then importing into Corel Draw works fine. Maybe it’s not flat (though the bounding box tells it is).

Is there an automatic way to have all hatches redrawn?

I tried _Make2D, but it doesn’t do hatches.

8

_ProjectToCPlane should place all hatches flat on the 0 plane… Along with all the rest of the stuff to be exported, which is probably a good thing to do for CorelDraw. --Mitch

9

The PDF exporter converts all curves to a series of polylines or Beziers. The PDF format does support arcs and circles, but the current exporter does not generate these entity types. I added a wish list item to do this in the future at
https://mcneel.myjetbrains.com/youtrack/issue/RH-44145

2 Likes
10

For whatever reason, Coreal doesn’t play well with a drawing treated with _ProjectToCPlane. The circle, that was drawn directly in the construction plane (!) becomes distorted upon import:

projected
projected1600×870 52.4 KB

Guess, redrawing all the hatches is - although tedious - the best way to go for now.

11

I’ve always had better results saving as AutoCad .dwg then opening in CorelDraw.

12

I tried that too, same result: misplaced hatches

Anyhow, after recreating all the hatches, import worked fine. (DXF)

13

“I import the PDF back into Rhino. Now the circle has a diameter of 988.494 mm. Wrong!”

I believe part of the issue here may be that the circle is located slightly out of the PDF page limits size and its getting scaled to fit with the limits.