Direct editing video

kevin_quigley

Just been reviewing the direct editing video in help. The first edit moving the face on the gear actually shows how capable the system is at face edits but also shows a classic case of where direct face editing fails. The point in moving that face would be to extend the gear, yet the move destroys the gear form. Now if you can move that face and maintain the gear profile I would be impressed! The move needs to incorporate rotation. Maybe not so easy?

brucebartlett

I must not have watched close enough because I thought the form did follow, I will have go back for another look.

brucebartlett

Your right @KevinQuigley‌the form distorts on the top of the gear but does seem to twist as the face extents. I may have to experiment with some of my own parts. Bruce

kevin_quigley

What it needs is some kind of "maintain shape' or 'maintain profile' option in the move. This kind of scenario is actually very common, and one of the reasons (at this time) why direct editing only tools like Spaceclaim cannot tackle many types of edits that in a history based system would be simple.

in this case all you would need to do is move the plane the sketch sits on, or move the plane and rotate the sketch/ amount of twist in the feature.

ACIS actually has the capability to add twist to an extrude, which makes creating forms like that very simple, so in an ACIS modeller like Shark or Cobalt all you do is make the extrude longer/more twist.

this is actually a very good example of how a mechanical design system still needs to tackle complex geometry and complex geometry edits. 

In that gear case you just want to move the end face, but at the same time maintain the end profile and continue the twist. Not that simple. But it is these real world tasks that will elevate OnShape above the rest...if they can do it.

brucebartlett

I tried get the form of this auger to extend and maintain shape but could not. I have made public if anyone else wants to have a go. 

caradon

I guess I'll have to experiment with helical gears!
However, I've already encountered situations where the direct editing in Onshape is easier, faster and more robust than doing the same changes in the original SolidWorks feature history.

Here's one example, that actually blew my mind:
1) Problem: Ribs need to be thinner.

2) Procedure: Move face with Offset on all vertical rib faces.

3) Result: BOOM. Thinner ribs!


I agree that the gear in that video is not a good example. I noticed the profile deformation too when I watched it.
Gears, springs etc. in my view should ALWAYS be driven by parametrics.

Dries

kevin_quigley

Dries, it is impressive but we need to consider the actual reality of editing native geometry. In SolidWorks, for example, editing the rib thickness is a simple feature edit. Direct editing really only comes into its own when editing non native geometry (and even then for relatively simple cases).

i've no issue with direct editing but its like it is a panacea for all CAD ills. Fact is, there are very few cases where direct editing beats history on native geometry. I'd personally much rather see development focus on better more comprehensive  features and surfacing. 

caradon

@KevinQuigley‌
Well, even in SW I use the direct edit tools all the time.
Especially for modeling clearances (think 3D prints) . Move face is very handy for this. For such operations I always use direct edits, because otherwise the parametric overhead would be excessive. How would you model a clearance with parametrics?
I think direct editing tools in a parametric modeling environment definitely have their place.

Purely direct modeler (like SpaceClaim) are another story. Ignoring any design intent is a no-go, IMO.
That being said, for working on imported geometry I still see value in a non-history-recording direct editing environment/toolset. Just for imported geometry.

Btw, changing the rib thickness in this case is not as simple as changing just one parameter (thickness) in the feature tree.
I explicitely dimensioned the minimal distance between ribs where they meet the side walls. So the rib layout resides in a sketch and is then extruded (no thin feature...).

Dries

kevin_quigley

Yes I use move face as well...it has its uses...just don't tell the SolidWorks police :-)

I model clearances in the sketches...easy to adjust then. No, seriously, direct modelling tools are great, provided we have the full complement of other modelling tools first.

ribs...still waiting for rib tools in SW like we had in VX and ThinkDesign. There, you draw your network then choose the zone you want the rib to apply to. Done. Having said that the SW ones are pretty good now.

caradon

@KevinQuigley‌
Agreed that core parametric modeling tools should be highest priority.

Dries