topic Re: Difficulty with Loft command in Form environment in Fusion Design, Validate & Document Forum

Difficulty with Loft command in Form environment

bosley_user — Mon, 15 Jul 2024 20:36:24 GMT

I’m experimenting with Fusion to carve furniture parts on a CNC machine at the Guild of Oregon Woodworkers. The idea is to carve or sculpt the front face of the chair’s headrail. For my first go around (see first screen shot) I used a traditional extrude feature with a lofted surface to cut away the front face, however this is very time consuming to modify.

I’m looking to use the Form mode for more flexibility in controlling the final shape. For the basic starting shape, I decided to create a loft between the two square sections and guide rails at each corner.

Unfortunately, the Loft tool in the Forms environment is not generating the same trimmed body as it does in the standard modelling environment. The two planar faces are not trimmed at all – see image Loft-FormFeature.png

I'd like to know if this is a valid approach or is there a better way to approach this problem.

Re: Difficulty with Loft command in Form environment

adam.helps — Mon, 15 Jul 2024 21:26:15 GMT

Lofting a T-spline surface in the Form workspace doesn't produce a trimmed surface. Instead, it aligns the true (untrimmed) boundaries of the T-spline surface with the rail curves. This ensures that the feature lines of your resulting surface will follow the loft curves. The expected workflow is that you'll start by lofting some curves, but that you will then bend or extrude the surface further by manipulating its control points (e.g. with all the other Form tools).

You can still trim your Form, but you have to do so further down the timeline. A typical workflow is to make an overbuilt version of the form that you require and then trim away the excess material after you have clicked "Finish Form." If you later need to edit the Form, you would do so by double-clicking the Form node on the timeline and making the edits, then running "Finish Form" again to re-run the remainder of the timeline (including any trimming).

Re: Difficulty with Loft command in Form environment

TrippyLighting — Tue, 16 Jul 2024 02:03:10 GMT

Can you post the model with that T-Spline loft?

I can show you how to get this quickly into something more useful but find it easier to explain in a video than typing it.

Re: Difficulty with Loft command in Form environment

TrippyLighting — Tue, 16 Jul 2024 02:06:14 GMT

@bosley_user wrote:

...the Loft tool in the Forms environment is not generating the same trimmed body as it does in the standard modelling environment.

The surface loft does not create trimmed surfaces. At least not in the screenshot you posted.

Re: Difficulty with Loft command in Form environment

bosley_user — Wed, 17 Jul 2024 18:44:49 GMT

Thanks Adam,

I'm starting over based on your recommendations, having more success by lofting the two curved walls then using the bridge tool to create the top and bottom flat faces. Thanks

Re: Difficulty with Loft command in Form environment

bosley_user — Wed, 17 Jul 2024 18:48:29 GMT

Thanks for your offer, my latest file is attached, please note that I deleted my first attempt after reading Adam's feedback. This time I lofted the curved sides and then bridged them to form the top and bottom faces. Still not sure if this is the best approach.

Re: Difficulty with Loft command in Form environment

TrippyLighting — Wed, 17 Jul 2024 20:11:53 GMT

The bridge command is what I would have suggested.

Re: Difficulty with Loft command in Form environment

bosley_user — Sun, 21 Jul 2024 16:34:37 GMT

Thanks for the help, I was able to get the desired shape using the box form.