Loft Command Problem

[oldtbone55]

Hello fellow users,

I'm running into an issue when I try to use the loft command to join several circle sketches that are at different heights in order to create a smooth recess on a guitar body where the control knobs will go. It worked for two of the controls but I can't get it to work for the other two. It doesn't seem to like the fact that the circle sketches for these two particular controls are intersecting some of the body contour lines. I used the project to surface command to project the circle sketches to the body. I've attached my fusion file for your reference as well as a screen shot with the error.

Thanks for your help.

Cheers!

[oldtbone55]

Hello Peter,

Thanks very much for the screencast. I sincerely appreciate it and the excellent explanation you provided. I think I understand what you were getting at about projecting sketches to a curved surface. I will explain how the rings you see in the body were achieved. I projected the rings that I created in an offset plane to the surface of the body first. Then, I moved each of the rings downward, except for the outer most ring, into the body. The center ring represents the diameter of the hole that's required for the potentiometer threaded shaft to fit through. It will be held in place with a washer and nut. To your point, this must be parallel to the bottom surface of the top and the cavity where it will reside. The remaining rings were there to be used to created lofts between all of the rings to create a tapered cavity for the control knob that will mount to the potentiometer shaft. What I did kind of worked for two of the sketches where there was no interference with the body surface lines but not exactly. I did it the way I did because I didn't know how to get what I wanted any other way. I've attached an image of what the recess should look like from a real guitar for your reference.

Thanks very kindly. I look forward to your solution.

[jeff_strater]

I still think that creating a "tool surface" is a good way to do this.  In this version, I created a Sculpt/T-Spline body for the depression, because I can copy that later, if I need to make individual tweaks to each instance of the cutout.  Adding a G2 fillet at the end will blend it into the body nicely.  My version has some curvature problems at the bottom, and ideally you'd fix those up in the Sculpt workspace:

[TrippyLighting · Accepted solution]

This turned into a much longer video that I was initially thinking, but there was so much wrong that had to be addressed.

Hopefully this helps;psyou to move forward with more stable designs.

This guitar certainly deserves a careful hand! Come back if you have questions, because I am eager to see the end product!

[oldtbone55]

Thanks very much Jeff. Your method does appear to be a good way to make the recesses in the guitar top. I'm going to go through it (at least a 100 times ) to soak it all in before I attempt it. 

Cheers! Happy Superbowl Day!

[TrippyLighting]

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@oldtbone55 wrote:

Thanks very much Jeff. Your method does appear to be a good way to make the recesses in the guitar top. I'm going to go through it (at least a 100 times ) to soak it all in before I attempt it. 

Cheers! Happy Superbowl Day!

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No, it isn't!

[oldtbone55]

Hello Peter,

 I can't thank you enough for just how much your screencast opened my eyes and for how much it is teaching me. This grasshopper has much to learn. The amount of information you have provided me in this screencast is phenomenal. Sometimes I've bitten off a lot more than I can chew but I guess no one has ever learned anything without making some mistakes. I will be reviewing your screencast numerous times as there is so much in it for me to absorb. All I can say is WOW! for now and offer you my deepest gratitude for taking the time out of your day to do this. I am going back to the drawing board with this and starting over. I'm looking forward to this project now more than ever. I will post back if I have any questions and eventually my completed project.

Grazie Mille! 

[oldtbone55]

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@TrippyLighting wrote:

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@oldtbone55 wrote:

Thanks very much Jeff. Your method does appear to be a good way to make the recesses in the guitar top. I'm going to go through it (at least a 100 times ) to soak it all in before I attempt it. 

Cheers! Happy Superbowl Day!

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No, it isn't!

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@TrippyLighting wrote:

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@oldtbone55 wrote:

Thanks very much Jeff. Your method does appear to be a good way to make the recesses in the guitar top. I'm going to go through it (at least a 100 times ) to soak it all in before I attempt it. 

Cheers! Happy Superbowl Day!

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No, it isn't!

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Well, not for some folks who'll bet on the game today anyways! 

[oldtbone55]

My bad. Jeff's way is one way of doing it, but not ideal. 

You win Peter. 

[TrippyLighting]

Ha ha ha. Ok. 

To be fair, Jeff's method of lofting is perfectly fine but works with 3D sketches.

That isn't in itself wrong, but does not create the geometry needed for this application.

If you had created "normal" splines and not used projected geometry this would have worked.

Whenever I work with curved projected sketches I check the curvature with tee curvature comb to make sure it's OK.

[oldtbone55]

Glad I could give you a laugh. 

May I ask what you mean when you refer to "normal" splines vs projected geometry? Enquiring minds would like to know.

Thanks.

[TrippyLighting]

I mean hand sketched splines rather than sketch entities or edges projected into a sketch.

[oldtbone55]

Thanks Peter. You're a gem.