I quit sketchup because of follow me.
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The follow me tool will "project" the face that you use as a profile perpendicular to the path (in this case the arc segments) and will extrude the shape that way. What you show is a typical "feature" of the follow me tool when making half domes. Briefly speaking; the tools works as advertised and works correctly - but in certain cases it creates results that are not what we like.
For this scenario, there are two workarounds:
- One is (as pointed out above) to draw the arc with an odd number of segments (or rotate a circle in a way that it's end segments are perpendicular to the diameter cutting edge if you wish)
- The other one is to do a full dome, turn on hidden geometry and delete half of it.
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Hi folks.
@gaieus said:
The follow me tool will "project" the face that you use as a profile perpendicular to the path (in this case the arc segments) and will extrude the shape that way. What you show is a typical "feature" of the follow me tool when making half domes. Briefly speaking; the tools works as advertised and works correctly - but in certain cases it creates results that are not what we like.
For this scenario, there are two workarounds:
- One is (as pointed out above) to draw the arc with an odd number of segments (or rotate a circle in a way that it's end segments are perpendicular to the diameter cutting edge if you wish)
- The other one is to do a full dome, turn on hidden geometry and delete half of it.
Personnaly, I always use the second method. Its is faster and less prone to error.
I use it a lot for piping elbows, for example. I create a full torus and then keep only 1/4 of it as a 90° elbow or 1/8 for a 45° elbow.
Just ideas.
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Anyway, mICHAEL, yes, I, and I'm going to go way out on this one, everyone else is often/occasionally frustrated by follow me and/or other quirks/unknown ways of SU. Working in isolation with no work-arounds, one might be inclined to quit. But we need not work that way; we can ask others who share our dilemmas. Sometimes, usually, they will help. Sometimes they are slow to take the bait, do our bidding, agree wholeheartedly, and this too we have to live with. Sometimes they snipe a little too quickly. There's not much to do about that; they are more likely to help, and help a lot.
Me, not so much.
That the face must be perpendicular to the circle might easily get lost (perp to a circle?), but as we see it is critical and in the help on the tool's use.
@unknownuser said:
You can use the Follow Me tool to create full lathed shapes using circular paths. To create a lathed shape:
Draw a circle whose edge will represent the path. Draw a face perpendicular to the circle. The face does not have to be on or even touch the circle's path. -
So Pilou's example shows it is completely understandable to be frustrated by this tool: his face is in no reasonable way perpendicular to his circle?
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Hum hum
The circle is on the flat ground, the face of the profile form is vertical!
So they are perpendicular!
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I would say that the face is perpendicular to the ground and to the plane of the circle, but not to the circle itself. But I accept yours as an explanation of why it works for your case.
Still, I say not so tight as is implied by 'understand and abide by the rules as stated and all will be revealed.'
Unless, perhaps, the usage were clarified to
@unknownuser said:
Draw a circle whose edge will represent the path.
Draw a face perpendicular to (the circle or to) the plane of the circle. The face does not have to be on or even touch the circle's path. -
Utter Gibberish.
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You can cut the circle after its rotation for keep the segments perpendicular
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@unknownuser said:
to draw the arc with an odd number of segments
I am affraid that the segments of extremity will be not perpendicular!
Arc of 25 segments 93.6°
(Arc of 24 segments 93.7°)
Arc of 23 segments 93.9° -
Partly this issue is due to follow me requirements (answer: get Profile Builder). Partly it's about working with SU arcs. True arcs would not give the problem in OP's setup.
I wonder in regards to half arcs and quarter arcs, and even in respect to the cardinal points of circles why does SU draw them one way (Noted 12 in picture) and not the other (noted 13)? I know that segments of equal length are given for arcs. But is that really any use?
Both arcs are from the same circle, or (for SU) represent the same half circle.
What if every arc started with half a segment. Or an alternate (hold option key down) provided this feature? I think the arc marked 13 gives a better shape and can be more usable in drawing, if those were the issues. Would it break some rule of logic, geometry, or SU?
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Assuming that the baseline is the same length, those two arcs do not share the same radius - the 'across the flats' version is slightly larger. This is because SU always takes the radius from centre to an apex - the standard arc has lines slightly within the drawn diameter, and No.13 extends slightly beyond.
Whether this matters probably depends on what you're modelling and what the purpose of the model is - but I think there does need to be a consistent method of determining the 'nominal' radius, for those folks who need to dimension their drawings.
A quick way to draw the alternative would sure be handy though. -
Actually they are from the same circle, so the base lines are not the same. So I see, the way SU defines the radius this would mean arc #13 would have other problems and an arch drawn with it would not dimension properly. I keep wanting to put "circle" and "arc" in quotes. The same issue we beat to death here, but not quite, regarding finding points that would easily be defined by a true arc.
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Doesn't TIG have some plugin that draws arc in this way?
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Sorry I must miss something!
How do you draw the "13" arc for have perpendicular segments without a rotation?
If you make a rotation, what is advantage to have odd number except kabalistic
I have not that!
(view top)
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It's my previous method above
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I did that but you showed it in more detail. Thank you.
Although it would be nice if SketchUP did real circles without vertices, we have to live with what it does do. It's not that difficult to set up the Follow Me path and the profile perpendicular to each other.
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I wonder if the OP has quit?
Lot's of great answers here but so far silence from Anarchist86ed.
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@unknownuser said:
Sorry I must miss something!
How do you draw the "13" arc for have perpendicular segments without a rotation?
If you make a rotation, what is advantage to have odd number except kabalistic
I have not that!
(view top)
[attachment=1:nfr6v75i]<!-- ia1 -->12-13.jpg<!-- ia1 -->[/attachment:nfr6v75i]That's how you do it.
I would think the answer to the second question was obvious, the point of our conversation.
I will continue to wonder about other ways of doing things and try to understand what is the reasoning.
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