This whole topic is so riddled with quirks and problems, it’s mind boggling. Excuse me saying this, but it’s true. It’s hard to know where to start.
Let’s start with this:
Apps like Revit or Archicad, who are damn good at 2D graphics (especially Archicad, believe me) have a strict separation between 3D space and it’s (automatic) 2D projections (floorplans, elevations, …), in which all the necessary 2D work needs to be done. They have a 3 step approach: 3D model space → automatic 2D projection space → layout composition space.
Rhino/Autocad only have 3D model → layout space, and like AutoCAD, it allows for 2D graphics (text, annotation etc.) in model space AND layout space. It does so because it copied the old concept of model / layout space from Autocad, which did it like this since the time when CAD only meant 2D CAD.
Although Autocad is capable of 3D, very few people use it for that (ugh!). Working in Autocad normally still means drawing in 2D. Thus, it does not make much difference if you annotate in model or paper space. It also happens often that Autocad people print directly from model space, which is perfectly possible.
Thus, people expect DWGs to show up nicely in model space, annotations, hatches, text and all.
Rhino, however, shines at 3D. This raises a complex problem: how to derive good 2D projections out of your 3D data, and - where to put this 2D data?
You Visualarq guys, of all people, should know about all the complexities.
There are a few ways to go about this.
- Put vaPlan/SectionViews into model space - but where there?
Disadvantages:
- The moment you move them side-by-side, you loose the absolute coordinate relation.
- The scene quickly becomes cluttered with all sorts of 2D garbage flying around, and keeping layers logical becomes a challenge.
- The 3D>2D projection engine is not yet capable of creating hatches, nor hidden lines (PLEASE do something about this!)
- Use ChangeSpace to put vaPlan/SectionViews into layout space.
Advantages:
- Clean model space.
- vaPlanViews even have a Scale parameter. However, for vaSectionViews, the Scale parameter is missing. Could you please add one? Thanks!
Disadvantages: - Dimensioning the vaPlan/SectionViews won’t show the correct measurements, and also, no good ‘Make 2D’.
- Use Detail views in layout space to look into the model space. (Your preferred option)
Advantages:
- Clean model space.
- Annotations in layout space ‘see’ the correct measurements.
- Shaded/textured objects
Disadvantages: - Does not translate well into 2D DWG!
Here’s a layout space screenshot of a simple test scene.
Rhino:
Sounds good.
After vaExportToDWG, this is the result in Autocad:
- 3D objects did not come across.
- Viewports were converted to bitmaps - that’s unsportsmanlike! The floorplan kind of works, the 3D viewport is garbage.
- Interestingly, the layout space annotations show a value (mm, but without scaling, no wonder).
What’s the conclusion… Rhino needs:
- a modern, parametric 3D-2D projection engine (like Archicad), which produces hidden lines, hatches, vector drop shadows, section styles… The new Section Tools are only halfway there. I’m not too happy with them.
- an additional 2D space, like the BIM apps have, to host all things 2D related.
Both are huge and expensive features, development-wise. But without, we will run in circles and never really get to a satisfying drafting solution.
My opinion. Thanks for reading!