Edges Coplanar to Back Faces of Objects Show Up in Background lines

Rhino
1

I am trying to use ClippingDrawings to help improve the drawing process at work, but am running into problems with the way they display information. It’s rare that we would ever have a sectioned drawing that only displays the sectioned plane of an object, so I am almost always needing to make the background curves visible.

This creates a problem where edges on the back side of faces and objects on the other side of the object getting sectioned are being drawn. I’ve tried a couple different solutions to this but haven’t found one that is satisfactory.

There is an option to have the clipping plane generate surfaces for each sectioned object. I can then manually go through each layer and move objects in front or to the back. But this doesn’t work when I have everything in a layout and need to use wireframe display to print to a pdf with vector lines.

The consequences is that on complicated assemblies where the ability to semi-dynamically update drawings from a model would be most useful, the amount of confusing and erroneously displayed information make them basically unusable in a professional context.

Does anyone know of a work around for this problem? Is it a bug? Would really appreciate any advice. Thank you!

Screenshot 2024-10-14 224347
Screenshot 2024-10-14 2243471806×1271 184 KB

2

Hi Andrew -

I’m afraid it’s impossible to tell from that picture what’s going on here. Can you post a simple 3dm file that illustrates the issue?

In Rhino 8, you can use any of the technical display modes to print to vector PDF. While there are still outstanding issues with this workflow, in many situations this should be a straightforward way to produce drawings.
-wim

3

Sure!

Here is a simple file where the problem is reproduced.

Attempting to recreate it with a simple assembly was helpful. It didn’t automatically happen as I expected when creating the section drawings, but rather only appeared when moving the ClippingPlane at what seem like random places along an objects volume.

The misdrawn lines also tend to stick after being rendered, but not always. At least now I have a few ideas of how to try and avoid these lines appearing.

Hope this is helpful.
simple_section_bug.3dm (521.4 KB)

4

Hi Andrew -

Thanks for that sample.
We have this issue on the list as RH-77424 Hidden background curves behind section plane are placed on visible layer
-wim