F360 Spline Bug found

[jpuhl777]

I'm fairly certain I've found a newly introduced BUG relating specifically to splines. The same lines that worked even a few weeks ago no longer work AT ALL.

I've done a bunch of testing now going from a file with many sketches to a fresh new file with two sketches to reproduce the issues almost every single time. I've never had any issues with these until very recently. NOTE: The fit point splines mentioned here are typically 3 points total and not very complex, which adds to the odd nature of these errors.

• Fully constraining a fit point spline appears to be impossible recently if ANY element in that sketch were copied into a sketch, even if that/those elements do not interact with the spline. This is VERY repeatable as of recently.

• Applying tangents to splines appears to be inconsistent now. Example: applying a fit point spline with 3 total points with the first and last points being tangent to the line they connet with results is wild movement or flipping the spline in an undesired way (making the line backwards or wildly changing the location and or shape). Note the tangent is being applied to the spline line, not any handles or control lines. This is VERY repeatable as well as of very recently.

• (Inconsistent) New spline lines often generate a warning of "Compute failed" - "failed to generate profile as, curves do not precisely overlap". Clicking undo to remove the spline and starting over sometimes fixes this but this is inconsistent.

Happy to provide more details if needed.

[g-andresen]

Hi,

please share a sample file file for reply

File > export > save as f3d on local drive > attach to post

günther

[jpuhl777]

Happy to, see attached F3D and screenshot. I can provide more detail as well.

I want to stress one thing - this worked perfectly up until roughly last week sometime (F360 update). I've done these lines MANY times now. I have old files that are have these same lines all fully constrained and did so without any issues at all.

[g-andresen]

Hi,

I can only recognize a temporary failure of the profile, which does not return even after a follow-up action.

günther

[jpuhl777]

I appreciate the video but two things

* The two splines on this sketch don't touch each other, they are seperate features. They do however both touch the projected spline but in different areas. Both are 3 point splines. Fairly minor but may make a difference in the end result because you are sharing the top point.

* you didn't fully constrain the spline. This is where most of the issues are occuring.

Note: I like to make many things in my designs parametric so fully constraining everything is key. That is where all the errors are JUST NOW coming into play. All this worked without issue a few weeks ago. This happened in the last 1 or 2 updates.

This is also a minimalistic example: the actual designs are much more complex with many sketches. My first thought would be I designed it poorly or did something wrong but all this worked very well before.

[jpuhl777]

Here is a full example. On the very last sketch there is a single spline, drawn to spec and it should be fully constrained, it has all required dimensions and constraints added but it will not flip to black. But again this is drawn exactly as I've done for over a year now without issue, many many many times and all of a sudden F360 does not accept it.

There are two circles unconstrained in the same sketch, they were fully constrained until the spline was drawn. I suspect if the spline can be constrained they will flip also. Ignore those two circles.

Thank you very much for the input and assistance. This is just frustrating me to no end because this halts my entire project and I have a lot of money in wood just sitting around waiting to be CNC'd.

[TheCADWhisperer]

In my opinion you are making your sketches way too complex.

I would break up into many sketches in my work.

I seldom use Symmetry constraints (or Mirror) there is usually a better technique to achieve symmetry.

[jpuhl777]

Note taken, however none of that exists in the first example given and there are the exact same issues. Do it doesn't appear those are the reasons why splines just now start having issues.

[jpuhl777 · Accepted solution]

This is not fixed.

However I found a workaround. Tested several times with different files to work. If interested:

1. On one sketch place a starting POINT and an ending POINT on the spline line where you will want the feature.

2. Create new sketch, project in the original spline line along with the two points.

3. Draw your new spline feature starting at the projected start "point" and ending using the project end "point". Sometimes you still have to make the spline coincident to the points.

4. This confirms the spline points are "known" by F360 in space, thus can be fully constrained.

5. Constrain any additional spline points in the middle as you normally would.

6. The spline end points can also now be made tangent (top point, then bottom point). Note sometimes the spline can flip backwards, so if that happens undo both tangents and try making the bottom point tangent first, then the top. Sometimes fixes that issue.

7. If number 6 does not work (like I said, this is a workaround), chose one point to be tangent and then you'll have to define the other points angle with a dimension line. 

Doing this I've have been able to make all my tests fully constrained.

[TrippyLighting]

@Phil.E can you check this out?

It would be nice if we could get some confirmation from the Sketch team if there were any recent changes on the sketch code. 

[Phil.E]

Sure thing, I've sent this report to them.

[sameer_babarNJS6C]

Hi @jpuhl777 ,
Thanks for reporting this issue, we can reproduce this issue from scratch with similar part.

We have started investigation on the same.

Meanwhile in such cases sometimes deleting and reapplying a dimension may trigger fully constrained analysis again and show the spline fully constrained. But ,this is only a work around we will work on actual bug soon.

Thanks,
Sameer Babar.
Autodesk Fusion 360 Team

[jpuhl777]

Thanks very much for confirming this

If you need additional information or anything just let me know. Happy to help in any way I can!