Attaching T-Splines to one another in the Sculpt Environment

[Anonymous]

Hi,

Fusion360 noob here.  I took advice from a couple of wonderfully helpful forum members about the electric violin project I have been working on in terms of how I can make it look more professioonal.  This resulted in my taking a series of sketches from the model and then rebuilding it in a loft.  After much fiddling I did it, and am most happy with the result.  My questions relate to finishing off the t-spline entry in the sculpt environment so that I can move to the model environment and start fitting the instrument body out with the other components it will need.

The model is attached.

My questions:

1.  I have three t-spline entities (and a fourth in another file which forms the scroll).  How do I attach those together so that they form one t-spline entity allowing me to close it and convert to a solid body ready for printing?  when I try to merge edges, everything turns to boxes and I have to undo.

2.   I note that when I click 'finish form' it does so with one t-spline entity with a gold surface and the others with silver surfaces. My guess is that this means there is an 'exterior' and 'interior surface value that autodesk is assigning to each entity, so how do I reverse these?  I wonder if this will solve the incompatibility issuein my previous question

3.  How do I tidy up the t-splines at the back of the instrument so that I can add a recess there as per my previous model? (shown in the thread here: http://forums.autodesk.com/t5/design-validate-document/smoothing-one-part-of-a-model-into-another/td... )

4.  How do I smooth out the faint crease lines on the model at the top of the back and in one instance underneath the model where the neck joins the body?

Thanks so much in advance for taking the time to read and reply to this,  with these changes I should be able to be pressing print in a mere few hours 🙂  I am so excited I can hardly wait!

best regards,

James

[jeff_strater]

Here are some answers, there are likely different ways to achieve your goals, depending on what you want the result to be, etc.

1. Combining the bodies.  You can try to join these at the TSpline level.  It can be very tedious, though, as TSplines can be a bit finnicky about topology.  This is usually the cause when the model goes into box mode - it means that the smoothing system cannot do its thing to produce a valid smooth model.  The other approach is to combine these at the BRep surface level, after the TSplines have been converted.  I did this in the screencast below.  The only danger here is I had to choose a really big tolerance (1mm) to get the stitch to succeed.  It may work, but you may have downstream modeling problems.  I did not try to go back into TSplines to fix up the TSplines to match more closely, but that would help.

In this video, I added a Patch to the top of the neck, to make the entire thing a solid.  I don't know if that's what you needed or not, but I wanted to test that it was valid.

2. Don't worry about the surface display.  Yes, your interpretation is correct.  The gray side is the "outward normal" of the surface, and the gold side is the "inward normal".  Mostly, it doesn't matter, because when you stitch them together, Fusion will figure it out.

3. I'm not really sure what "tidying up" you want to do, but if this is the recess that you are referring to in the other thread:

I would not attempt this in TSplines.  I would do that as an Extrude Cut after the model has been converted to a solid.

4. I'm not really sure which crease lines you are talking about smoothing.  In the solid I made from your design, it looks pretty clean, but then I'm probably not looking at it with the same critical eye as you are.  In general, though, this kind of thing requires some TSpline fiddling to get right.  Lots of small changes, then look again, then change some more, etc...

Hope this helps you continue to make progress.  Excited to see the final result.

Jeff Strater (Fusion development)

[TrippyLighting]

As Jeff said, combining these T-Spline surfaces can be very tedious in Fuaion 360. Thus I exported the control meshes into .onj fles, imported these into Blender and did some general clean up. It still could use some work!

Here are a few points:

1. Try to model in quad surfaces as that helps keeps the topology clean.

2. Use only as many polygons and edge loops as you absolutely need. Rather start with too few and add as needed to give you the necessary detail level.

3. Use creasing as a last resort. It will help improve your modeling skills 😉

If understand it correctly your intention to 3D print this. Be prepeared for some learing. This is a large object to be 3D printed in one piece. You may have t re-model certain parts put stiffening ribs in places etc.

The project you are attempting is not a beginner project, so KUDOS for that!

[Anonymous]

Once again I am bowled over at how helpful those responses were thank you both!  I need to go through the video and play with the file, will comment on that later, but before I do, I just wanted to say thank you.

ps.  the recess is below your arrow.  the bit you are pointing at is the housing for the electronic tuner rig, the part I need to recess is the gap between the tuner rig hole and the connecting port at the bottom which will enable the user to access the tuner control panel.  eh, too much info...tl;dr  It's the bit under where you are pointing 🙂

[Anonymous]

Jeff.strater:  Thank you again for your video, I appreciate the time and effort that goes into doing this to answer some random stranger alturistically online.  In terms of the patching, I have worked through your workflow with this project and on some rudimentary shapes so as to get as good at it as I can.  I am learning that knowing when to move from the sculpt environment to the others and shut off the sculpt options is a skill in itself!  re. your response to my fourth issue, they were small cosmetic imperfections in the surface rather than creases along edges which would likely be less than visible when the component was printed anyway in hindsight so I probably shouldnt have been fussing.  I guess I could call them 'stretch mark's as TrippyLighting's revised mesh doesnt feature them with it's better laid out edges and vertices.

TrippyLighting:  Thanks so much for doing that with the mesh!  As I can't really comprehend the work involved in transferring something into Blender and then performing magic, I am going to assume that it is relatively tedious and dpeendent upon a significant prior experience set, so I am enormously grateful.  It gave me chills to look at the body with all the edges in easy to manage layouts (yes I'm sad, but I am so invested in this project now that seeing it come together is most gratifying!).  Your three pieces of advice have been noted down and followed religiously since and I have done some practicing on less complex shapes than the whole violin body to get a little more experienced at it.

As a result of each of your assistance, I have been able to make a stellar amount of progress in a short time.  Attached is the body, now edited, converted to a solid body patched and filled, with some of the components positioned to give an idea of the final configuration if you are interested in where the project has gotten to by this stage.  In terms of the 3d printing process I accept that it is going to be difficult to do, luckily I have a good friend who is somewhat of an expert at this and he is going to walk me through that process when I have the model finished to my satisfaction.  In the mean time I shall have a CF support structure down the body of the instrument and at other relevant points and there shall be no problem with printing it in separate pieces and attaching those to one another to deal with the size of the printing bed:  It will be painted so any such join can be filled and hidden appropriately.  That said, I havent ever 3d printed anything myself (or even seen a 3d printer in the flesh at this point!) so I am steeling myself for many unforseen issues to come!

Next step is to position each component properly in relation to the body (I assume I can align in relation to a plane or axis or something as the body has no flat surfaces from which to position: I'll figure it out) and engineer the interior cavities for the components and carbon fibre armature which will strengthen the finished instrument.

[Anonymous]

Oops, max file size exceeded:  Have a screenshot instead 🙂

[TrippyLighting]

First of all, awesome progress. I am excited and looking forward to see the finished product!

This is going to be the first space alien electric violin ever built 😉

The workI did no Blender was 2 parts:

1. Joining the meshes. It was a little bit of work but it was quick work. I could make a multi part video series about al the tools Blender offers for modeling that would be awesome to have in Fusion. The T-Spline editing in Fusion is intuitive but somewhat clunky compared to tools such as Blender that are optimized for pure speed.

2. Cleaning the mesh. A lot of unnecessay edge loops were removed and also a good number of no quat polygons coul be eliminated. this took most of the time. 

[jeff_strater]

That is very cool!  Amazing design.  Can't wait to hear how the 3D print process goes, and to see the final result.

Glad we could help in some smal way.

Jeff