Thicken in certain direction

MBartlett21

I would like to be able to thicken a face so that the thicken direction at the edges = cross(MYVECTOR, cross(MYVECTOR, surfaceNormal))
I would still like to have the thicken amount directly out from the face though.
@lougallo ?

MBartlett21

@billy2

Ruled Surface FS:
https://cad.onshape.com/documents/d17d93235d69e6ec8f815b80

Sometimes works unpredictably for some edges.

billy2

Cross at edges for direction? Isn't that what thicken does?

Are you looking for an extrusion? Couldn't you copy the surface and create the joining surfaces, then enclose to make a solid? 

MBartlett21

I am looking for someting like this. (It doesn't work that well)
https://cad.onshape.com/documents/d17d93235d69e6ec8f815b80

billy2

Ok, it seems easy enough. The offset direction is based on the connecting sheet?

Is this true?

MBartlett21

It shouldn't be.

The direction of the edges should be perpendicular to the axis selected

billy2

was thinking this, but it didn't work:


Not sure what you're crossing. Cross axis to what?  I guess this is your question. 

billy2

How about this?

cross these:


to get a normal (I think this is what you have):


I think you need another cross, cross these:


to get this, is this the direction you're looking for?:


you'll need 2 crosses to get the direction. I think.

MBartlett21

Yes,
that is currently what my FeatureScript tries to do

billy2

When you're done with that, and you're looking for the next FS, could you please look into this. There's one thing that OS won't do, and it's the only thing that I can think of that I need. I'm dreading the day when I really need it and it's not there. It's a ruled surface. I use it a lot in SW and trying to mimic it is something I'm not sure I could do. This FS that you are currently writing is very close to a ruled surface generator.

Pick an edge and enter a length:


Ruled surface normal @ a distance:


I use this pattern so much and I worry that I'm going to get caught one of these days. The full FS should ask for tangent or normal and possibly an angle with tangent being 0 and normal being 90 degrees. 

I'm being asked a lot about surfacing inside OS, and honestly, I have no hesitation when designing with surfaces inside OS. This is a pattern that I use a lot, and with some trickery, I can approx. it, but it takes a lot of work and I don't like approx'ing.

It seems like you're controlling direction at a surface's edge, and then building a surface with a certain magnitude would be easy?

MBartlett21

That ruled surface normal that you showed, did you use thicken then offset face?

MBartlett21

@billy2

Ruled Surface FS:
https://cad.onshape.com/documents/d17d93235d69e6ec8f815b80

Sometimes works unpredictably for some edges.

billy2

I offset a surface, then lofted, then hid the top loft surface to make it look correct. You can't always do this and it's a long ways to creating a ruled surface. I'm not even sure it's correct.



Let me dig through your code and see what's going on. I thought there would be an edge selector and then: normal, tangent.

I'm not sure what "Direction" is doing.

Do you mind me poking through your code?

billy2

I believe the direction is a derivative of the surface at it's edge. I'll see if this is available in feature script.

Direction shouldn't be constant.

billy2

Looking through feature script library, I saw no reference to opExtrude with a direction based on a 3d surface.

opOffset on the other hand says it uses the face normal for the offset direction. Bingo!

So...

We can use the solid variant or the surface variant of the offset. After looking at the results using the UI to build both cases, I like the surface variant.



So this means the input to this featurescript would be a face(s) and edge(s).


An issue would be, when OS offsets a face, do you think you could query these edges, are they related some how so is it easy to match respective edges? 

The next step would be to loft between the matching edge(s).

And then lastly, delete the offset surface.



What I like about the surface offset:
-we won't lose the original surface id and won't break down stream features that referenced the original surface.
-we can new/add the lofted surfaces
-hoping we can apply opDraft to loft surfaces

This would be huge, something SW can't do easily, adding a 2nd direction:



Ultimately why? Offset curve on surface is something simple CAD just doesn't have, but it's a recurring design pattern when designing complex shapes.

Here's an example of a ruled surface in action, the orange is an offset of the ruled and then a split & delete face was performed cleaning up the original blue surface's edges:


Many times you want to clean up bounding edges to a 3d surface and doing this with sketch geometry is impossible.

The 1st time I ran into this design pattern was creating rivets around the door of an airplane. Manufacturer wanted them equal distance from the door's open. 


 This might be out of scope of our original conversation, good news is it's doable.

billy2

Looks like opDraft can draft these lofted surfaces. Ignore everything thats talks about neutral plane and the rest is about reference_entities.


I think feature script could build a good ruled surface generator.

MBartlett21

Can you use thicken?
It may be faster than lofting

MBartlett21

You should be able to use opEdgeChange or opExtendSheetBody for trimming or extending your surface

billy2

My fear with thicken is that the resulting body might re-assign the selected surface reference id's

As a result, you'd have 2 surfaces:
-the original selected surface
-the one bound to thicken

I get why thicken is better, you don't have to construct lofts  keep track of edges trying to match them. 

But you still have query solid and match up with selected query edges. This I think is the toughest part of this whole featurescript and I'm not sure which is the better approach.

I'd be happy with either, 

MBartlett21

I can use startTracking(context, originalEdge) for each edge at the start to get the faces and edges coming from that edge

MBartlett21

@billy2
I have created a version with more options now, can you try it out?

billy2

Ok this needs a better name and should be released in a surface tool bar:




Shortening is also included:

holy crap, why is this a secret?:

billy2

Ok, I going to delete solidworks from my computer and make room for some mp3's. 



pattern it around:


yeap, clean it up:

MBartlett21

@billy2
Then you can use this feature to turn it into a part:
https://cad.onshape.com/documents/84d939daceef6a928b8abcba

What should I call the feature?

brucebartlett

Nice one, with a little push from @billy2

I think I going need a Morgan Toolbar soon.

MBartlett21

@brucebartlett
@billy2
What should I call the features below?

Feature Name             Description
opExtendSheetBody: Extends a surface body,
opEdgeChange:         Changes edges on surface bodies,
opCreateOutline:        Projects faces and parts onto an extruded surface or plane

billy2

Used enclose, can you give me rights to copy opBoolean Surfaces?


I liked to see how you do it,

As far as naming goes, I don't know. I like Bruces suggestion "Morgan's Magical Toolbar".

owen_sparks

How about "Just give me an Onshape job already" toolbar?

brucebartlett

owen_sparks said:

How about "Just give me an Onshape job already" toolbar?

You need to do the Onshape Summer Internship or have you just started your own Australian Summer of Onshape Featurescrpting. 

The tools name would maybe be "Surface Extent", "Edge Replace" or Edge Transform".

I had a little play, I don't do much surfacing so a little rusty. For starters I thought I'd try offsetting some faces to get a even chamfer around a freeform shape but run into trouble here. https://cad.onshape.com/documents/01cfeaa7438b5325e7560233/w/083e880a30d5cb926f7de56e/e/40503249aaa96a34057a9ff6 

MBartlett21

@brucebartlett
Can you try using the opEdgeChange FeatureScript?

MBartlett21

billy2 said:

Used enclose, can you give me rights to copy opBoolean Surfaces?

@billy2
The document is public, so you should be able to copy it.

PS: the feature can work between a surface and a solid (It returns a surface trimmed to the solid)

brucebartlett

That doesn't seem to work either, it always fails after pulling the first edge back.