Chamfer or fillet does not work on edge, all around the part

[ardelean78]

Hello, noob here trying to make a chamfer all around this simple part but it won't let me.

Somehow in the drawing perhaps not all lines are connected, but I tried over and over connecting them as best as I know how.

I traced this outline off a canvas photo using spline line thing, and used a couple of circles at 2 of the corners to get the corner nice and round.

I've done quite a few designs (all basic) and usually have no trouble with such simple task, but I've never traced a design off of a canvas with the spline line thing.

Thanks ahead!

[jeff_strater]

turning on curvature display in your sketch should give you some hints.  These wild fluctuations in curvature are probably the source of the failures:

zooming in on the one on the right, you can see some problems:

smoother curves, less abrupt transitions will help.

[laughingcreek]

as jeff says, the curvature of the sketch splines will give you problems.  with splines less is more.  those splines could each be done with just 2 points followed by adjusting the tangent handles. the curvature quality will be easier to control. see attached model.

Also, really tight curvature, like you have at the corners, can cause problems.  a possibility for that is to use solid fillets AFTER applying chamfer.  again, see model.

lastly, a suggestion.  model around the origin and take advantage of part symmetry (ie-draw half, mirror the solid).  sketching will be easier and model will be more accurate.  once more, see model.

[ardelean78 · Accepted solution]

@jeff_strater Thanks so much for the reply! That was not the problem. I re-did the whole thing with fewer spline points and same issue (moved original to the side, and did a new spline line around, as shown in the photo below).

I did find the solution in a video.

But first I tried deleting the circles because I thought they just weren't "connecting" with the line, so I just made those two bottom corners 90 degrees. Did not solve the issue.

Solution: Apparently with a spline you have to add dimension to each section/line in order for it to be "defined".

Here is the video that shows the solution https://www.youtube.com/watch?v=ynBl9XJesDs

[ardelean78]

Thank you so much for the pointers! I found a solution just now and posted it.
And yes, I really ought to learn that mirror trick as it would save me time.
Cheers!

[laughingcreek]

so you didn't apply any of the advise given in that video. namely, use as few points as possible (you used a gazillion), and fully defining the curve (you don't have angles defined for any of  the tangent handles.)  what's happened is when you redrew the curves you just happen to get the curvature good enough that you where able to get the chamfer to work by shear luck.  you don't actually know why it's working (or why it didn't work before).  that means you'll just bump up against this problem again, and you still won't know how to fix it.

fwiw, the suggestion from the video of fully defining the spline handles is a red herring.  totally unnecessary.  most of us here don't bother for fit point splines.  (control point splines are a different story)

using as few points as possible is important though.  you'll note on mine that each curve segment just has 2 points (and don't have any dimensions).  look at the curvature combs on mine and compare them to you curves, you'll see a dramatic difference.  that difference will translate to any solid you produce from it, producing less than ideal surface quality. in the case of an extrude the surface will feel wavey to the touch.  if you ever want to do something a bit more complected, like lofting, your troubles will just be compounded.

is you part symmetric?  looking at your dimensions you can see what your modeling sure isn't.

[ardelean78]

Oh man! I thought I had it figured out lol
When I drew the outline the 2nd time I tried to chamfer the part and still didn't work. Then I added the dimensions and I don't know what else happened but it worked.
You are definitely right, I got lucky on some step.
And thank you for bringing my attention to the file you attached - I hadn't noticed it before! You made it look too easy. It gave me a chance to practice on the left side (trying to make it look like the side you did) and yes I got a better understanding of the spline and adjusting it by those little antennas. I was way overdoing it with those! There was a selection tool in Photoshop I had used long time ago to crop out items, and that one required lots of little lines to contour around something, so I was using this tool in the same fashion, which I now understand was wrong.
Thanks a lot for the input. I will practice the mirror tool to get it symmetric next time 🙂

[jeff_strater]

yes, what @laughingcreek says is correct - fully defining the sketch will have no effect on downstream fillet/chamfer of an edge from that curve.  What will have an effect, though, is tangency.  Make sure your sketch curves are constrained to be tangent to adjacent curves using a tangent constraint.  Curves that are "near tangent" with adjacent curves are known to cause downstream problems with fillet/chamfer.

[HughesTooling]

Doesn't look like you need to use splines at all. 

Just lines and a couple of arcs then 3 fillets on the body before mirroring. See attached file.

Mark