Plug-in for creating Sectional View

Rhino Developer
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Greetings,

Just as a name of my topic suggests, I would like to develop a Rhino Plug-in for creating a Sectional View. Why not just use a “Make2D” command? Well, because it has some issues. Consider the case shown on image 1. There you can see an “assembly” which consists of a simple shaft with some cutting blades. On image 2 you can see the Front View of a “sliced” geometry using Clipping Plane. Now consider the result of a Make2D command which is shown on image 3. As you can see, the resulted section consists of an awful amount of incorrect and redundant lines, even though the only command option I’ve checked was “Clipping plane intersections”. Image 4 and image 5 shows only the lines on Intersections and Curves sublayers respectively. Now compare the lines from Make2D with with the result of a “Section” command, shown on image 6. As you can see, the outcome is far more superior than from Make2D, though it also has some false geometry. The reason for the existence of those false lines lies with the problem of tolerance. You can see it from the images 7 and 8. The section is made just on a boundary between blade’s cutting surface and cutting plane.
Ok, now when the scope of a problem is described, I sincerely would like to hear some suggestions on how to create a tool, that would avoid the issues mentioned before and provide a Sectional View with hatched cuts. I admit, I’m not a professional software developer and I have some basic skills in C++/C# development. But I’m ready to spare some time on trying to create this Plug-in, because it is essential for making a descent technical drawings in Rhino. Please, share your thoughts and suggestions on how to achieve it.
P.S. My first thought was to use the Section command, improve it by adding hatches to the closed polylines and then move to the more complex problem on how to create projected lines for the geometry beyond the cut of a section plane. But it seems that with SDK I need to create the whole concept of Section myself using Rhino.Geometry.Intersect namespace, am I right?

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Img 1. 3D model of an assembly (Shaft with Blades)

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Img 2. Front Section using Clipping Plane

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Img 3. The result of Make2D command

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Img 4. The result of Make2D command (“Intersection” sublayer)

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Img 5. The result of Make2d command (“Curves” sublayer)

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Img 6. The result of Section command

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Img 7. Perspective View of geometry sliced in half using Clipping Plane

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Img 8. Perspective View of lines from the Section command

Make2d_Example.3dm (3.0 MB)

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Hi @crow ,

While this isn’t an answer to developing the tool as a plugin, have you looked into Rhino 8 recently and seen if the new section tool/model hatches, etc. work for your purposes? I’ve been using them quite a bit for architecture projects and while the subject differs from your use shown here, the geometry is similar in that it’s comprised of many breps/surfaces contacting each other (walls, doors, windows, etc.)

Anyways, having the ability to dynamically hatch the section cuts and control the boundary edge widths and colors as well covers most needed use cases in my projects.

May be worth checking out on your end prior to starting development on a dedicated plugin.

These posts are little “old” by now but summarize the feature in R8:

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