Cant loft

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1

Hello, I am stuck with lofting. Did lofting before but these rings do not want to. Shapr does not state what its problem is, but I can not loft these closed control point rings. Why?

Bildschirmfoto 309
Bildschirmfoto 309834Ă—1010 186 KB

2

Loft works with closed profiles that don’t have holes. To achieve what you want, loft the internal profiles, then loft the external profiles, then subtract the internal loft from the external loft.

2 Likes
3

Szia István, why does this work then? Also “holes”. The only difference is I did an offset back then but then I could not add control points to the outer rim. I was then told to do a copy to have control points. I did that, well a scale which is the same idea, and now I can not loft. Or is the problem the inner hole?

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1788Ă—1014 135 KB

4

Hello again,
This works, because it is a single, closed loop.
In the picture above you have a closed loop and annother closed loop inside - that does not work due to the restrictions of the algorithms (basically the parasolid-kernel - its the Same in Solidworks for instance).
But the part you are modelling is likely to have a constant wallthicknes (moulded parts should have)

  • just delete the inner loops
  • make your loft
  • apply a wall-thicknes feature
  • smile!
    Cheers Matt
1 Like
5

Hello again,
This works, because it is a single, closed loop.
In the picture above you have a closed loop and annother closed loop inside - that does not work due to the restrictions of the algorithms (basically the parasolid-kernel - its the Same in Solidworks for instance).
But the part you are modelling is likely to have a constant wallthicknes (moulded parts should have)

  • just delete the inner loops
  • make your loft
  • apply a wall-thicknes feature
  • smile!
2 Likes
6

yeah still cant loft

I btw love white text on light grey surface that vanishes after a couple of seconds. Always a funny read as when you get close enough to the screen its gone. Has some slapstick.

1

the next one is said to self intersect. Is it?

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2431Ă—605 63.2 KB

I answer myself. Some of the planes are too close which seems strange to me honestly.

7

Skipping some layers worked but the Wall thickness tool (shell) does not. So no smile yet.

8

My guess (I can’t tell without access to the data) is, that its not the distance between the sketches, but the different amount of sketch-elements per sketch.
In ideal the count of sketch-elements is the same for all sketches.
Sometimes it also works if that is not the case. Let me give you an example:

2022-11-24 17_14_56-Shapr3D
2022-11-24 17_14_56-Shapr3D632Ă—672 159 KB

Here I made a Loft between a rectangle and a pentagon. Due to the different count of sketch-elements, the algorithm had to decide for me where to put the fifth point. That means 2 things:

  • I lost a little control over the resulting geometry
  • It may be the case that the algorithm does not find a viable solution for this task, what causes the operation to fail (because it would end in an self-intersecting body, what could not be calculated by the kernel due to the zero-thickness-error)

I would propose to check your sketches and to make sure that there are as few elements as possible / as much elements as needed (and I think you could handle that with 1 Spline per sketch). Then the lofting should be easy!

2 Likes
9

Sure thanks but I dont really want to make you work, its already nice of you to help here. Also you know this is how one learns. I even start being able to read white on white :slight_smile: