CurvesWB Gordon Surface Issue

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Eagletrike
Posts: 12
Joined: Sat Jan 02, 2021 11:26 pm

CurvesWB Gordon Surface Issue

Post by Eagletrike »

Hi,

I have been attempting to design a seat for a motion sim. I plan to make it out of fiberglass, so the idea was to design the seat to put into my sim design, extract the inside of the seat to 3D print a mould/plug to shape the seat. After numerous unsuccessful attempts, using Part design WB (Not overly experienced at using CAD). I saw an excellent series made by Mango Jelly on the curves work bench. I went with using B-spline rails for one side of the seat then mirroring them, then adding the B-splines for the profiles. The Gordon Surface was then applied to create what looked like what I was after, unfortunately it has a couple of flaws in it, these were further exacerbated when a 3D offset was used on the Gordon surface.
Curves Fail_B_splines Full picture.png
Curves Fail_B_splines Full picture.png (11.96 KiB) Viewed 382 times
This is the finished B-spline frame before applying the Gordon surface
Curves Fail_Gordon.png
Curves Fail_Gordon.png (244.55 KiB) Viewed 382 times
From what I can see is that it has added a extra flap of surface which I have circled in the above picture. I have tried adding a couple of extra B-splines and smoothing the bends but it hasn't made any difference.
Curves Fail.png
Curves Fail.png (266.68 KiB) Viewed 382 times
The above picture is after a 3D offset was applied with infill added. It shows Further defects which are the two top red circles, These I can't find any obvious defects in the Gordon surface before the 3D Offset is applied and the lower two circles indicate the result from the extra flap from the Gordon surface.
Just hoping someone can point me in the right direction, I appreceiate your help in advance.

Regards

David




OS: Windows 7 Version 6.1 (Build 7601: SP 1)
Word size of FreeCAD: 64-bit
Version: 0.20.25065 (Git)
Build type: Release
Branch: master
Hash: 4de2ad46b2b9c78ac2721a0dbea7c19306261095
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.0
Locale: English/Australia (en_AU)
Attachments
Flight Seat ver mod B_spline Curves WB Rebuild.FCStd
(78.38 KiB) Downloaded 19 times
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GlouGlou
Posts: 3352
Joined: Sun Apr 05, 2015 9:02 am
Location: La Rochelle, France

Re: CurvesWB Gordon Surface Issue

Post by GlouGlou »

Looking your curves, I think you should better use sketches or interpolated curves instead freehand curves. Because it's better to have some continuity around corner and accurate curves. You should merge some points as well. As you seat is symmetric, you can work with only half curves (if its easier for you)
Attachments
Capture.JPG
Capture.JPG (27.41 KiB) Viewed 272 times
Eagletrike
Posts: 12
Joined: Sat Jan 02, 2021 11:26 pm

Re: CurvesWB Gordon Surface Issue

Post by Eagletrike »

GlouGlou wrote: Sun Sep 19, 2021 6:28 pm Looking your curves, I think you should better use sketches or interpolated curves instead freehand curves. Because it's better to have some continuity around corner and accurate curves. You should merge some points as well. As you seat is symmetric, you can work with only half curves (if its easier for you)
Thank you GlouGlou for your feedback, I will research your suggestions and see how I go, just thought I was so close as this has taken me weeks through so many different versions of the design.
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