No Trimming in Sculpt?

[Bill_Brehm]

I was searching for how to trim in sculpt only to find that I can't.  I'm trying to make an auto body, but can't get the surface off the wheel well opening.  Do I need to sculpt the wheel wells?  Also, later when I need to put in opening for ducts, how is that done if I can't trim out an opening?

I like the tutorials, but they really leave out a lot of information as to how they do what they are doing.  I watched one guy trim out the wheel wells, but he never mentioned how it was done.  Would have been interesting considering you can't do that.

[TrippyLighting · Accepted solution]

Trimming is really not something that is done when modeling with T-Splines. At least not when in sculpt mode.

There is a 3 part series on Youtube of how to model a vehicle body with T-Splines in Rhino.  While the controls of course are quite different, the general approach to modeling a vehicle is very much applicable of how this is done with Fusion 360.

Another suggestion would be to watch tutorials for car modeling for any of the mainstream Subdivision Surface modeling softwares such a 3DS Max, Cinema 4D, Modo, Blender etc.

Subdivision modeling is very similar to T-Spline modeling. 

You can actually trim a T-Spline body. In order to do that you'll have to click Finish Form and the T-Spline is automatically converted into a solid body if the T-Spline encloses a volume "watertight", or it is converted into a open surface body, which is likely what will happen with a car body.

Then you can change into the Patch mode, create a surface and trim/split the open surface body of the T-Spline with that surface.

[Bill_Brehm]

OK thanks, I'll try that.  I also found that I could draw a spline to shape the wheel well, then use the 'Match' command to make the edges match that.  I'll also watch the subdivision tutorials videos.

[PhilProcarioJr]

@Bill_Brehm

Although I added the request for a trimming tool in the IdeaStation, this can still be done with the current tools. It just has to be done manually. The simple answer is you model your T-Splines without the opening and make sure you have edges that follow the opening shape then delete the unneeded faces after you are done. If this doesn't make sense and no one beats me to it I can make a video later if you would like.

On a side note I have yet to see anyone use T-Splines in Fusion the correct way (IN MY OPINION) for making a car body. So what would be the correct way, simple the same way real cars are modeled in the software made for making cars. You should lay out a bunch of 3d splines that define major curves of the form. These splines can be dimension driven and accurate. Once you have these splines you can snap your T-Spline edges to them creating the proper openings that will be CAD accurate. Using this approach is a lot more technical and would require a very detailed video showing the concept if you don't understand what I am explaining here now. Unfortunately I don't have time to make these videos right now, but I can make one showing the first technique later today.

Another reason you really want to use these guide curves is it will give you a clean base with the correct number of points to snap to, sort of a guide to a good clean layout of your T-Splines.

@TrippyLighting suggested trimming after conversion, I prefer to work the other way around and by that I mean to make a base shape from surface patches, convert that to a T-Spline then shape the new T-Spline to the finished form. It's a lot faster, way more accurate and a lot less frustrating. I'm still amazed by the lack of good information on T-Spline modeling that's currently available....

I hope this at least helps some.

Cheers

[Bill_Brehm]

I think I understand what you are saying, I'll try it.

I've been following the method used in this video. https://www.youtube.com/watch?v=WkUvyYegWNk   It sounds a lot like what you have described.  I spent the last few days just trying out all the tools.  I call it scribbling, but at least you don't have to worry about trashing your project.

The learning curve is really steep if you are doing this on your own. I'm going to look around at the local tech schools to see if they don't have something useful.  In the meantime there are many more videos to watch.  Hope we'll be adding yours to the list.

Thanks

B

[subversivespeed]

TRIM t-spline is the tried and true method when creating and reverse engineering. All you are doing effectively, is matching the edge of a t-spline to an existing t-spline face. There "is" a way to do it without having to do all this sideways nonsense, however I haven't stumbled across it yet.  TRIM t-spline to surface or t-spline face is one of the most powerful and useful tools ever conceived. 

Fusion folks, lets try to keep workflows at least somewhat similar to those to which we are already accustomed. We don't need to reinvent the wheel, we just need to make it more robust and roll easier and more efficiently. Having to thicken the whole thing to make it into a solid 3d model invalidates the reason we use t-splines ie quick edits and flexibility. Also, I get it. do a finish design and then pretend its all cool, but, then, can you go back to t-splines if further editing is required?  If not, then, you can easily end up having redo after redo. It really should be able to be done all within the t-spline module. 

[subversivespeed]

Ok, looks like if you convert it to BREP, you can then go into PATCH and perform the TRIM command as one would presume. However, in my case, I have a assembly with 20+ laminar flow louvers and Fusion crashes or simply will not allow you to select say 20+ T-spline items and convert them to BREP all at once in a batch operation. It must be done one by stinking one... Ugh.. 

Ok, well, there goes an idea that will be a very good workaround: allow multiple T-spline selections to be converted to BREP. Simple and solves multiple problems and the same time and gives us an efficient workflow. 

[Anonymous]

Hi. Direct trimmin' in Sculpt mode would be nice. 
Sometimes Naive tweaks work fine, so this is how I would cut a strip from a Body, being the strip intended as a ribbon around the Body.

So in Sculpt environment you will:
1. make a copy of the Main Body
2. draw two guide splines in place of the strip to cut

3. close sketch

and enter Surface environment where you will

1. extrude the splines

2. trim a strip off the Copied Body

3. thicken it outside,
and as a result you have a ribbon around the Main Body.

👉Remember you can always head back to Sculpt environment from the Timeline. Keep things simple though!

In case you would like a more professional advice I suggest you this video. Enjoy:
https://www.youtube.com/watch?v=hRwdzwYd5iU