create a flat pattern of my skis, not working...

[Anonymous]

Hi! I try to create a flat pattern for my skis but it ain't going very well. I'm not too familiar working in sheet metal so I may have done something wrong.

Any solutions?

[johnsonshiue]

Hi! I suspect the body does not have uniform thickness (3mm). It is because if I thicken it to exact 3mm, I am able to create a flat pattern. I have not identified where exact inconsistent thickness is. I can take a second look later.

Many thanks!

[Anonymous]

How do you thicken it to exact 3mm? Isn't that what I've done, I tooked the line which I created the lower surface with and maked an offset line 3mm from it, how could that be something else than 3mm?

The weird thing was also when i wanted to make that offset line because I first tried to project the lower surface line to a plane and then make the offset but I were not able to do that !? I couldn't mark the line, couldn't use it.

[johnsonshiue · Accepted solution]

Hi! I think I have found the source of the numerical inaccuracy. It is in Sketch8. The construction curves are projected from the 3D spline edges to 2D Sketch.  Then you created offset curves from the 3D projected construction curves. This is not a desirable modeling practice. It is because the projection of the 3D edges does not necessary equal to the cross section. Projection depends on the project direction and also the project tolerance.

The design intent calls for cross section, then you should create either 3D Intersection Curves or 2D Project Cut Edges on YZ plane. Then create offset curves from these cross section curves.

The quickest way is to simply use Offset/Thicken command, select the bottom faces, and intersect upward to 3mm. You will see the flat pattern can be created (see attached part).

Many thanks!