how to solve this in Fusion: half rounded cap

[cekuhnen]

it is a particular tricky part in Alias.

Fusion tools give me not very satisfying resuls - see zerbga

[Anonymous]

Thanks to educational screencasts by Michal in the past, I was able to make what I think is a good result. 

The first loft needs to be present (tan below).  Then for a second loft, be sure to turn off the sketch at the edge of the first loft.  Then turn off Chain selection so that can select only that one edge of the first loft as Profile 1. Then profile 2 was the sketch on the horizontal plane (added it by pressing New Input, then if desire can turn on chain selection for ease of selection for 2nd profile).  And finally a rail (turning off first chain selection again if I turned it back on for Profile 2, then pressing New Input again) that I made by projecting the curve you had into a sektch, and finishing it with a spline with tangent constraints at its ends (didn't think about using smooth constraints, but that would be another option). 

Cool challenge!

Jesse

[Anonymous]

Oops forgot to mention that during the second loft I then clicked on Profile 1 and chose Smooth for Continuity (between the two lofts).  This option was available because Profile 1 was the edge of the first loft, not a sketch, as I mentioned. 

Jesse

[Anonymous]

And I should also just mention to be accurate, that for making the rail curve from existing surfaces, I used the Intersect command, not project. 

Jesse

[cekuhnen]

Hmm this approach also shows some pinch issues. Specifically the problem here is where all the isoprams run together into one corner.

The exports in Alias show also most G1s not being concistently G1.

[Anonymous]

Hmm, yeah.  Although, @michallach81 also covers patching out problem points like that (second vid by Michal on this thread http://forums.autodesk.com/t5/post-your-tips-and-tutorials/archtop-guitar-modeling/m-p/5676762#M508)... So that's what I tried doing with yours, and after an experiment it works pretty good it looks like.  First this shows what we're dealing with. 

So I made a construction plane that splits the end of the body there, and then used patch with tangent continuity condition (seemed to look better than curvature for the patch).  To get the best surface results, I did some stuff, but please not I just ran through this and am not sure what's actually necessary or not.  I first made a sketch well below everything and projected the bottom edge of the "pillbox" onto it.  I then did two lofts (was not able to do one) to complete the loft from the bottom edge of the pillbox to the sketch beneath it.  I did curvature continuity, so that the nonvertical slope of the bottom of the pillbox (this could have been made vertical if you desired) would continue in the lofts beneath, resulting in the slope seen below.

There is actually a tiny gap between the two lofts, that I reduced by adjusting the direction control of one of the lofts.  They were successfully stitched with a slightly increased tolerance from default.  For no particular reason I then split the bottom loft surface so it wasn't so tall (for some reason this split got an unclean edge as seen in below image).  The first split and patch I did was not as good, so I moved the splitting plane back to create a larger hole in the pillbox to patch, and that gave the below result.

As I said there's something strange happening at the bottom edge, but for the most part it looks like Michal's technique is very good for getting high quality surfaces. 

Jesse

[cekuhnen]

also the Alias patch tool can be g0 to g2 along each side
fusion fails to abe able to have surface continuity along rail edges grrrr

I think that is what breaks the zebra in your version

[Anonymous]

Haha, the current limitations shure get to you it seems 😉

It seemed there was actually some little bug happening there with the body split (causing a kind of extra little bit extending past the split line), did not look into it much since I'm not actually using this or anything.  No rails were used in this case (except of course the rail for the original rounded end).

Jesse

[cekuhnen]

now I am confused can you share the fusion file?

I am quite fit in Alias but sometimes Fusion drives me crazy which is why I was posting this. sometimes I am not sure if I am in a too much alias workflow.

[Anonymous]

Wow that must be interesting trying to jump around between these different programs, a true modeling wizard 😉

So I took your advice and used a a single rail to insure the two extended lofts touch each other with no gap.  In these cases where curvature is low near the area of interest, having no G1 or G2 control on the rail sides is not really a problem (but obviously in other cases it would be nice to have, although I'm sure it's fairly involved to execute such a network of control as you said). 

Out of curiosity I then tried just a circular patch of the trouble area.

Next I did a plane slice/split body, but only patching the small area (with sharp corners).

 

Finally I did a full patch, which included the cut into the cylindrical region as well.

I also attached a .f3d of just the last body, as well as the experimental model (tester.f3d, but note it's a mess due to scrubbing timeline around trying all kinds of stuff). 

Jesse

[Anonymous]

Note that the the spline used for a single rail for both lofts (temporary lofts) was made in a new sketch, and the spline was made smooth constraint, as a continuation of that arc curve, at its one end. 

Also an interesting tidbit is at one point I was getting an error making the circular patch, so I copied and pasted the body into a new component (don't know if that was really needed) under Create Base Feature mode, and then worked fine.  But that error seemed like a kind of fluke, never ran into it again anywhere. 

Jesse

[Anonymous]

Ok I also tried using your cool sweep surface, and got good results.  For some reason doing a loft for that shorter shoulder/corner section, does not appear to create pinch issues, perhaps because there is less slope/steepness??

[cekuhnen]

Yeah looks like this is currently the only approach to it. Maybe when Fusion has better / improved surfacing tools such round shapes would be more possible with a better underlaying mesh because the zebra shows issues and when you analyze 

I did an Alias approach cutting in edges so the patch tool has 4 edges to work with:

Blue is the loft surface so the patch with G2 is a tick better along the center line you can see how the loft dips in

and the weight handles seems not to do much here

the zerba is not too bad but also there are some issues and the curvature comb shows it even better the surfaces have a lot of noise at the edges

here a different view showing that sometmes G2 is maintained and sometimes it breaks

[Anonymous]

Using curvature combs like that is cool.  With that shorter shoulder loft, I forgot to use a centerline rail as I did before.  So I tried it again, this time making a rail via a spline from the intersection curve of the sweep, to the top loft intersection line.  I tried two different continuity constraints, first tangent for the spline, then smooth.  The latter gave better results. 

So here is an off center curvature test for the rail spline with only tangency constraint that is rough:

And here is the result with smooth spline end constraints. 

In order to adjust the weight of the smooth coincident constraints, I followed the procedure Nathan showed at:

https://screencast.autodesk.com/Main/Details/c4084682-ca66-4b0c-890c-0bb0a5107dda

adjusting the weight handles until got a good curvature (and being sure to first fix/anchor the curves and curve endpoints).

This was the curve where part was used as a centerline rail.

I'd say the results are pretty good.  I would be interested if need to even more close to perfect, if additional rails from splines also with smooth end constraints would lead toward that goal.

Jesse

[Anonymous]

Forgot to mention, to edit the dimensions of the tangent handles (for the smooth constraint), first had to drag and select everything, then right click to choose Break Link.  Then overconstraint was not an issue.

Jesse

[cekuhnen]

 enough for me today - the sketching and surface tools have so many bugs Fusion today hit the "cannot use it button again".

[cekuhnen]

so the pinch issue of the loft command could be helped out by cutting out the area and patching in a new surface - not good or ideal but currently leads to usable results.

His video is pretty good but he makes a blend curve in a new sketch. Try what he is doing in one sketch 😉

I cam to the conclusion that those hanles are not suitable for an effective and usable workflow. We just need a dedicted blend curve so you can build you splines

and then patch a blend curve inbetween. The thing is if you change the handles for the blend curve your previous curves will be changed and that is useless.

here is a vid:

https://drive.google.com/file/d/0Byzv_NlyKp_2RDd1eGx6QmV6RlU/view?usp=sharing

[Anonymous]

That looks like a really good result!

I'll look at the problems you were having later.  I see in other threads you included the .f3d file, be sure to do the same for any other issues/bugs you were talking about in this thread.  I will also look at all your videos later.

When I was adding dimensions to tangent handles (for smooth constraint), I first had to unlink everything so no more purple.  Then I would add activate tangent handles and add Aligned dimensions to the tangent handles, but would not change their values (note a fairly easy way for me to select a tangent handle is to just zoom in significantly).  Then I would Fix just any splines (not their endpoints), and would also need to fix for straight lines their endpoints so that they would not slide.  Of course the actual spline being adjusted was not Fixed.  Then I would change the handle dimensions to desired value/driven value.  In that sequence it worked.

Jesse

[cekuhnen]

@Anonymous

thats what I would usable blend curves either via start endpoint and weight values or as a CV curve aligning points

this tangent handle spline I just cannot get used to no matter how much I use it. It feels cumbersome complicated and hard to control.

really only ideal for making blend curves in a new sketch.

https://drive.google.com/file/d/0Byzv_NlyKp_2N3BYNy1rQjV3bjg/view?usp=sharing