(novice) Just trying to loft two triangles into a tetrahedron...
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(novice) Just trying to loft two triangles into a tetrahedron...
(freecad v. 0.20.1)
As you can see from the attached file, both triangles are fully-constrained, closed sketches. When I select the two sketches and hit Additive Loft, I see this:
Based on the tutorials I've seen, that looks correct. But when I hit OK--
I'm not sure what's left for me to do. If someone has an alternate way of lofting between vertices, or from vertices to a point, I'd like to learn it.
As you can see from the attached file, both triangles are fully-constrained, closed sketches. When I select the two sketches and hit Additive Loft, I see this:
Based on the tutorials I've seen, that looks correct. But when I hit OK--
I'm not sure what's left for me to do. If someone has an alternate way of lofting between vertices, or from vertices to a point, I'd like to learn it.
- Attachments
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- spaceship.FCStd
- (46.96 KiB) Downloaded 12 times
Re: (novice) Just trying to loft two triangles into a tetrahedron...
The wo triangles share a common edge. This leads to a so called self intersection which is forbidden. Consider the loft as an elastic wire which is moved from start to end section. This wire must not touch a second time a place which it had touched before.
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Re: (novice) Just trying to loft two triangles into a tetrahedron...
One profile can be a vertex. You could use one triangle and a vertex to solve your problem; the path would define one of the connecting edges, similar to this one: Edit: Oops, sorry, The image belongs to an Additive Pipe example, not Additive Loft. And so Additive Pipe holds the solution to your problem.
- papyblaise
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- Joined: Thu Jun 13, 2019 4:28 pm
- Location: France
Re: (novice) Just trying to loft two triangles into a tetrahedron...
This is it
In order not to have a coplanar, you move the sketch by 0.1mm in Z and make a Loft
Your sketches are open, vectors are coincident with the external references (in purple), they must be joined together, for that use the polyline tool and then constrain
In order not to have a coplanar, you move the sketch by 0.1mm in Z and make a Loft
Your sketches are open, vectors are coincident with the external references (in purple), they must be joined together, for that use the polyline tool and then constrain
- Attachments
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- fface.JPG (17.99 KiB) Viewed 906 times
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- spaceshipPPB.FCStd
- (44.56 KiB) Downloaded 8 times
Re: (novice) Just trying to loft two triangles into a tetrahedron...
Would you please provide the source of that example? I'm having trouble conceptualizing how a pipe can exist without a line to follow. Or... a line outside the pipe? And I don't see the word "outline" anywhere in the Additive Pipe tool itself.FBXL5 wrote: ↑Mon Nov 14, 2022 9:04 amOne profile can be a vertex. You could use one triangle and a vertex to solve your problem; the path would define one of the connecting edges, similar to this one:
pyramid.png
Edit: Oops, sorry, The image belongs to an Additive Pipe example, not Additive Loft. And so Additive Pipe holds the solution to your problem.
Re: (novice) Just trying to loft two triangles into a tetrahedron...
The source of the example is: PartDesign_Examples
The examples have paths outside the object so that they are visible.
You can exchange the word outline with (closed) sketch or cross-section and a path is the line to follow that can be straight or curved (2D/3D).AidanofVT wrote: ↑ I'm having trouble conceptualizing how a pipe can exist without a line to follow. Or... a line outside the pipe? And I don't see the word "outline" anywhere in the Additive Pipe tool itself.
The examples have paths outside the object so that they are visible.
Re: (novice) Just trying to loft two triangles into a tetrahedron...
Heh, I was actually looking in the right place on the wiki; the examples were just collapsed.FBXL5 wrote: ↑Tue Nov 15, 2022 2:08 am The source of the example is: PartDesign_ExamplesYou can exchange the word outline with (closed) sketch or cross-section and a path is the line to follow that can be straight or curved (2D/3D).AidanofVT wrote: ↑ I'm having trouble conceptualizing how a pipe can exist without a line to follow. Or... a line outside the pipe? And I don't see the word "outline" anywhere in the Additive Pipe tool itself.
The examples have paths outside the object so that they are visible.
For those who come here in the future, I'm attaching an example of how to accomplish what the example shows.
For me in the present, though, I'm unable to apply this technique to my model. Sometimes I get gibberish errors, sometimes I get "Failed to validate broken face," sometimes I get "Command not done." I'm guessing I'm misunderstanding something basic about what constitutes a line, what constitutes a closed shape, etc, since these lines are also the edges of shapes. I'm attaching an updated version of the model which I think is even cleaner than the last one. If anyone can pull this off, I'd really appreciated a step-by-step of how you do it.
- Attachments
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- polyhedronExample.FCStd
- (11.49 KiB) Downloaded 10 times
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- spaceship.FCStd
- (48.9 KiB) Downloaded 9 times
Re: (novice) Just trying to loft two triangles into a tetrahedron...
That's how it looks if you use the green triangle as an outline, the white line as a path, and the end point of the path as a second "outline":
The green triangle = Sketch002 is used as a Profile.
Sketch004 is used as Path to sweep along.
And with transform mode Multisection selected the endpoint of Sketch004 is used as an added Section.
It would be nice to have a hint that the selected element is not the whole sketch but only one point.
Usually added sections are used to create transition objects (from one profile to one or more sections) and a transition into a pointed tip is just a special case. And in 3D:
Now I switched to English and I see the dialog like this:The green triangle = Sketch002 is used as a Profile.
Sketch004 is used as Path to sweep along.
And with transform mode Multisection selected the endpoint of Sketch004 is used as an added Section.
It would be nice to have a hint that the selected element is not the whole sketch but only one point.
Usually added sections are used to create transition objects (from one profile to one or more sections) and a transition into a pointed tip is just a special case. And in 3D:
- papyblaise
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- Joined: Thu Jun 13, 2019 4:28 pm
- Location: France
Re: (novice) Just trying to loft two triangles into a tetrahedron...
you can also make a loft between a point (top of the pyramid) and the triangle
- Attachments
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- spaceshipPPB2.FCStd
- (40.45 KiB) Downloaded 11 times
Re: (novice) Just trying to loft two triangles into a tetrahedron...
The polyhedronExample is a good example.
The task dialog lists the element of the sketch that is use for the path = Edge1.
It would be nice if Add Section would work like this, too.
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I'm sorry if I have supplied some redundant information, but I wanted to try the snip tool.