T-S Self Intersection warning a little too extreme! ?

[cekuhnen]

This is not really a manifold sub-d surface. the only thing is that one end of the handle flows and cuts through the bottle body but is otherwise not connected in anyway to the mesh.

thus I find the error warning rather odd and problematic because this would mean that you cannot use sub-d in a way well you can use sub-d without TS.

Any insight? A way to not make Fusion refuse this?

[PhilProcarioJr]

@cekuhnen

Separate in the middle of the handle shown in the picture, when you convert the object you can stitch them back together.

Ideally in a case like this Fusion should convert the T-Spline into a surface so you can deal with the intersection after conversion. There are also many other ways this could be dealt with to but anything would be better then failing the conversion. It just doesn't make much sense. The software could also do an automatic trim between the offending surfaces which would also be great.

[cekuhnen]

The self intersecting idea is ok and useful to prevent well bad self intersections

but in this case there should be an overwrite button to still produce the nurbs patches

in patch mode I could easily extract the faces trim them accordingly and then stitch everything back together

[TrippyLighting]

If it is not already in the Idea station , please put it there and link it back here.

I remember another thread with a very similar topic. I am sure we can gather a few more votes. Here is one  @michallach81

[jeff_strater]

Why not just use Bridge to join the handle to the body?  That's how I've seen it done in the past.  Then, you wouldn't have the self-intersection.

Jeff

[TrippyLighting]

The keyword here I believe would be topology.

Try to merge two different diameter cylinders with different numbers of cylindrical segments.

The end result will not look nearly as clean as you'd get with combining two solid cylinders of different diameters.

[cekuhnen]

@jeff_strater That only works if the topology allows it.

Proper slim topology focused on maximizing detail match with the least amount of CVs is really king in that discipline

when you want smooth transitional surfaces and not some wobble sub-d model.

In the situation with the handle the CV count does not match anything at the bottle surface

You can see that the cap was possible to be included easily though.

You suggestion in this case is not practical and actually bad practice because it would needlessly overcomplicate the mesh.

"a 3 point curve is easier to manipulate and maintain a smooth curve then having 7 points to deal with"

[Phil.E]

Sounds like some great new suggestions for Idea Station.

I manually tried the suggestions presented here and had no problem performing the workflow in Patch space. So at least for now you can complete the workflow. Here is what I did:

While it's a T-Spline, make it not intersect. That solves the intersect problem.

After it's converted to a Patch body, split the handle.

After the handle is split, extend it into the bottle, trim out the bits you don't want, and stitch it all together again.

Shell it and you are done.

The thumb abides.

Found a few things you might notice, so I'm logging bugs on this:

1. Split body seems to extend the cutting plane really far without checking "extend".

2. Cannot intersect the Patch body across itself, which doesn't seem right, hence the need for splitting the handle.

3. Logged improvement to convert T-Splines like this into Patch bodies if possible, linked to Idea Station posts. (you still have to vote 🙂 )

Thanks,

[cekuhnen]

@Phil.E

From my experience the split command is great if there is nothing else that later might intersect because of the current habit to over extend.

I am also not a fan of the extend command as Fusion does not provide much control over it.

Thus I rather prefer building the surface as I want with TS and then trim where needed.

Idea is posted:

http://forums.autodesk.com/t5/ideastation-request-a-feature-or/overwrite-self-intersection-warning-w...

[Phil.E]

Thanks for posting the idea. I hope that the workflow you want can be done eventually.

There is a way to get more control over splitting bodies that I had forgotten to try with this model yesterday. If you sketch the line used as a splitting tool there is a lot more control over it. Just wanted to show another solution to splitting since we are talking about it.

[cekuhnen]

This is all true but ideally the splitting command adds more geometry than needed.

Look this is better and cleaner:

pre create an additional surface to trim the bottle and make handle shorter

in my case I decided to make the cutting tunnel also bigger so I can blend surface without the need of a fillet later (2 in one task)

cut the shape open

loft blend the two openings

done - no other geometry changes nice and clean

[TrippyLighting]

As a learning exercise I've created my own object to see if I could replicate the steps discussed here. While that does work I find it's still quite a hack!

By far the easiest solution would be to allow a T-Spline to simply convert with some self intersection. I'd like for Fusion 360 to be a program that by default assumes a certain intelligence and expertise of the user.

I'd much rather explain it from this perspective to a new user and warn of the traps and dangers involved than being limited in this way, despite the fact that a conversion would still create a valid, self intersecting surface. Unless of course there is some algorithmic or math at play that does not allow that.

[jeff_strater · Accepted solution]

An update on this topic: we discussed a solution to this problem that would do what you want. Not promising a date, but there is a solution that would tolerate the intersection

Jeff

[cekuhnen]

Hey that great! Thanks for considering this