Start with Orthographic Projection rather than Sketch?

paul_rayner

Hi
I'm trying to evaluate OnShape for use in our Design classrooms. The process we usually follow is to start with Orthographic projection. My initial (and favourable) forays into OnShape all show students starting with a sketch, creating an Isometric view, and then developing (or letting the application) develop the Orthographic views.
So, can I start with Orthographic view drawing in OnShape, learning how to start with a plan, and then developing elevations - have I just been looking in the wrong places?

S1mon

Orthographic projections of what? Mechanical block shapes, houses, ???

Onshape is fundamentally a 3D modeling tool. The 2D views in the mechanical drawings are outputs of the 3D models. 

That said, much of the 3D modeling starts with 2D sketches. It's certainly possible to use the sketcher to draw plans and elevations (of architecture?) which aren't necessarily going to be driving 3D models.

Here's a really simple example of a plan and elevation with no 3D geometry. 

hairy_kiwi

Hi Paul,

What follows is opinion only, offered in good spirit. 

That's an interesting approach you propose, but I suspect one that neither Onshape nor many other CAD tools is particularly best suited to, in my somewhat limited experience and humble opinion*.

In the 70's - 80's my father taught technical drawing to an advanced level. I can't help feeling the understanding he instilled in me of the fundamental concepts in developing various projections from isometric views - using paper and pencil - is still as valuable today as it was when I was growing up. The ability to eventually sketch an isometric view only strengthens the ability of the mind to conceive and iterate design changes more rapidly than could be done using CAD alone - even now I feel.

That ability to sketch and iterate from a concept takes practice, and even if those sketches are rough and only for personal use, there are many who still believe in the value of that skill vs diving into CAD from the outset. Quite coincidentally, I came across a great video recently by designer/inventor/YT celeb Jeremy Fielding, which shares my thoughts (and many others) far more eloquently and engagingly as he discusses the fundamentals of learning to design. I've fast forwarded it to his thoughts on conceptual sketching:
https://youtu.be/TbWFRvMV3gw?t=4m02s

*FWIW I recently needed to do some reverse-engineering, from a dimetric projection into a solid, in CAD. I used MoI3D for the task, because it has the ability to easily and rapidly do wireframe sketching in 3D space, while viewing from one or any of the three isometric views or the 3D view itself. Perhaps kids are capable of learning faster these days and equally, I'm not doing this kind of thing professionally, but that took a fair degree of brain power to get my aging head around just to set up; starting from an isometric projection would have been easier, but I didn't have that luxury. You might perhaps make a great teaching module from such an exercise, but overall I feel it would only be of some edutainment value – learning to sketch is akin to learning first principles and if they are sound, I can't help feeling most everything else can be derived.

Much respect and all the best in endeavouring to make education engaging for the next generation of designers and engineers!

edit:
Apologies Paul, I just re-read your post for the third time and looks like I got the wrong end of the stick in terms of the projective geometry you hope to use Onshape to teach. Are you perhaps trying to surround a 3D CAD solid in the primary elevation views, and then relate those elevation views to the orthographic view by rotating or 'unfolding' them? If so, the unfolding idea might be performed by way of a FeatureScript, but that's a job for someone more conversant in OnShape's capabilities - and definitely a hack considering how Onshape is intended to be used.