how to tell sketch curve direction

[metd01567]

Simple question: how can I tell which direction a sketch curve is pointed?  And should I care - it seems to affect some of the CAM operations, e.g. cutting a 2D slot for a profile swept along a path.

[etfrench]

You can toggle the direction of a toolpath in CAM by clicking on the red arrow.

[Anonymous]

Can you please share some visuals of the problem so we can understand the problem better?

RISHI ADITYA SHARMA
STUDENT EXPERT at AUTODESK

[metd01567]

Yes, I do that, but in a crowded contour the red arrows are often hard to interpret.  I played with it more, maybe I asked the wrong question.

I'm trying to cut a slot along a chain of sketch curves. I've isolated a single chain in the attached drawing.    A similar forum question was solved using a 2D contour to CAM operation, selecting one side of the slot as a contour.  I modeled the finished piece using a sweep, but couldn't convince 2D contour to use one side of the slot.  Then I tried selecting the sketch curves directly, which I was able to do.  But 2D contour didn't stick to the curve.

So I'm kind of stuck.

[HughesTooling]

Should ask questions earlier before too much frustration!

Anyway you're selecting the contours wrong, you should select as one not 14 individual curves.

Mark

[metd01567]

I re-generated the toolpath (same version that I attached previous post), and the contour is better behaved.  For this one, I individually selected each curve from the "Slots" sketch, and set direction left to right:

The toolpath is offset from the centerline of the sketch, which is how it should work.  I should be choosing one side of the modeled slot, but I can't seem to manage it.  Here's what happens when I choose the top side of the slot's bottom:

I was able to select one side of the slot, until I reached the end.  There it wraps around as shown, which isn't what I wanted.  The toolpath wasn't generated with an "Empty toolpath" warning.  

[metd01567]

OK, got that thanks.  That still leaves me with a toolpath offset from the centerline.  Any suggestions there?

[HughesTooling · Accepted solution]

Try the attached, I've turned compensation off so you can use your centre line. Also look at tangential extensions, set to minus the cutter radius. I've disabled leads but if the plunge is too much you could enable Ramp and several steps for depth.

Mark

[metd01567]

Great - plunge with no lead-in works fine. 

I'm still curious about my original question, is there ever a reason to care about which direction a sketch curve is pointed?  If so, there there a way to visually show that direction?

[HughesTooling]

Don't think it really matters and no there is no way to display the direction. Just did a little experiment and it looks like sketch offset always defaults to offset to the right for lines. Also looks like circles\arcs are anticlockwise and offset to the right if selected on their own. Of course this will depend on which side of the sketch plane you're looking from.

Mark

[metd01567]

Thanks for the help.

Tom

[metd01567]

Well, I applied the solution to the full-up design, and that went fine. 

That brings up a question about workflow for future designs of this type. I was able to redo the whole design using only 2D sketches.  I'm pretty sure I'd spend less time doing the design that way, should I even bother with a 3D model?  I can always extrude and sweep if the need arises in the future.

[metd01567]

OK so I never give things a rest.  It bothered me that the CAM 2D slot operation didn't work on my 3D model.  So I was missing something.

I saw a post suggesting that CAM 2D Slots "just work" with sketch slots.  I played with approximating my spline using arc slots.  It dawned on me that the sketch slot ends are rounded, where mine are flat.  I chopped a cylinder out of each end of my 3D slots, and the CAM 2D Slot operation now works fine on them.

The main problem with the 3D workflow is creating all the profiles, one for each slot and oriented correctly.  I'm working on a script for that.  If I add rounding the ends of the swept body, a 3D workflow will be very slightly faster.

[HughesTooling · Accepted solution]

I hadn't really looked at the design itself before. Here's how I'd do it using plane along path then sweep. You could use a user parameter for the cutter diameter to make edits easier. See attached file, I added a parameter for the cutter so changes will update slot width and end fillet rads. Press Shift+P to edit parameters in the design workspace.

Mark