Printing Back Edges in High Quality

I can’t find any way to export a PDF with back edges as dashed lines in high quality.

Using the print dialog, I can use a PDF printer driver, but I get either low-quality dashed lines with even ultrahigh definition, or no back edges with high accuracy HLR.

Using the Export → 2D Graphic dialog, I can’t find any way to get back edges in the export.

Using layout, I also can’t get high quality back edges, since they’re low-quality no matter what raster settings I use, or not shown in either vector or hybrid modes.

Back edges are a raster feature, that is why they won’t export to a vector file.

The only workaround I know is to use LayOut:

  • In SketchUp, create two versions of the same view, one as a wireframe view.
  • In LayOut, overlay the two views, then explode the wireframe view and set the linetype of the resulting group to a dashed line

The downside is that you will have to redo the aligning/exploding every time you modify the underlaying model.


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Another way to achieve dashed lines, although a bit more convoluted, is to

  1. draw the entity in solid line in the .skp file,
  2. draw perpendicular lines that intersect the previously drawn entity
  3. erase between the perpendicular lines to create the dashed effect. (also remove the perpendiculars as well)

I use this method to portray doorswings for example in SketchUp models. The technique translates very well in Layout for condocs also. You merely place the dashed doorswing on a specific layer that is turned on or off depending on the visibility desired.

In that case, the first complaint is valid: raster quality of dashed back
edges is horrible when printing to a PDF driver, and I’ve tried several.

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Bryce Schober

The old trick to get high-quality raster output from SketchUp is, I think, still valid:

  • export to PNG or JPG to a very high resolution (or about double the resolution you need), with antialiasing off.
  • downsample the image in Photoshop or your image editor of choice to the final resolution.

Note that for colour printing, 300 DPI is the highest resolution you need, anything over that just adds to file size but does not show in the final product. The quoted DPI of a printer doesn’t take account of the dithering needed to produce colours.


Be advised that the example I provided is a vector output, not raster. The image is a SketchUp file with no alteration. The dashed image reads in the same manner when imported into Layout using the method delineated. Also note that the line thickness may be adjusted to suit the preferences of any modeler.