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I want to make a shape like the picture below.

I used an Archemedian curve spiral to make a shape for the slide, because I want the upper part of the spiral to have a smaller radius than the lower part. But now I am stuck on what to do next. I tried putting an extruded half circle on the curve, but that doesn't do anything.

So, what to do next after creating my archemedian curve spiral? (2nd picture)

enter image description here

enter image description here

EDIT: I have now been able to make the shape that I want. I used an archmedian curve and converted it to a mesh. Would you know how I could cut the shape in half? I wanted to delete faces, but the faces sort of rotate as you can see in the third picture. So 'just' deleting faces is not an option.

enter image description here

EDIT: File

DPlayground
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4 Answers4

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An Archimedean Spiral primitive with the settings as below will do it:

enter image description here

... followed up with Solidify and Bevel modifiers. This can be converted to a mesh when you're happy.

I guess it's almost as easy to sweep a Curve Primitive > Arc along a Curve Primitive > Spiral in Geometry Nodes, for the base-object, in which case you're non-destructive all the way.

Robin Betts
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Switch the curve to Twist Method > Z-Up:

enter image description here

It should work:

enter image description here

You can still play with the Tilt value of the control points if necessary (in the N panel or shortcut CtrlT):

enter image description here

File:

moonboots
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  • Ah, the z-up twist method makes a huge difference! But how do you see both the mesh and curve? If I convert my curve to Mesh, the curve is gone. – DPlayground Sep 07 '23 at 08:48
  • Also, after I have extruded along normals, the bevel modifier is not working. – DPlayground Sep 07 '23 at 08:50
  • I have used a mesh that has an Array and Curve modifier, but doing it with a curve works as well, as for your bevel problem, please share your file – moonboots Sep 07 '23 at 09:11
  • Can you show me how you did that? Here is the file for the bevel? I added the file – DPlayground Sep 07 '23 at 10:06
  • It's not clear where you want to bevel, if you want to bevel the edge, put the Bevel modifier Angle at 90°, also put the Subdivision Surface below the Bevel modifier, also maybe you want to put a Solidify modifier at the top of your modifiers stack in order to give a bit of thickness? – moonboots Sep 07 '23 at 10:13
  • Also I've edited my answer and linked the file – moonboots Sep 07 '23 at 10:27
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Another alternative would be to use the XYZ Math Surface from menu Add > Mesh > Math Function > XYZ Math Surface:

enter image description here

This option uses the following Parametric Equations, but only copy/paste the right side of the equal sign for each equation into the $X,Y,Z$ $equation$ fields:

$$x(u,v) = (b*(a+u*f)+a*\cos(v))*\cos(-u)$$ $$y(u,v) = (b*(a+u*f)+a*\cos(v))*\sin(-u)$$ $$z(u,v) = -a*(\sin(v) + u*c)$$

where a is the radius of the arc/tube, b is the tapering radius of the whole spiral setup, f is the tapering amount, and c is the height. Set $V max$ to the value of $\pi$ by typing in pi in that field to get half tube result. Add Solidify Modifier and then Subdivision Modifier to get this:

enter image description here

Harry McKenzie
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  • It does work for me to a certain degree. The only thing is - the beginning and end of the slide are also connected? Also, doing this type of math has been too long for me haha. Not really understanding what I am doing also doesn't help probably. – DPlayground Sep 07 '23 at 09:29
  • yeah bit tricky i just added this solution to add more variety and some may find it useful – Harry McKenzie Sep 07 '23 at 09:54
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There must be an already existing answer to this somewhere… Here's one way to do it:

  1. ⭾ Tab Edit the Default Cube.
  2. With everything selected SY0↩ Enter, to flatten it.
  3. MB remove doubles.
  4. 2 for edge selection mode, select the top edge, XE delete it.
  5. ⭾ Tab Object Mode.
  6. ✲ Ctrl4 Subdivision Surface.
  7. Add Screw Modifier.
  8. ⬆ ShiftA, EP Add an Empty.
  9. Select the mesh object again, set the empty as the axis object of the screw modifier, increase the screw value.
  10. GX Move the object on the $x$ axis.
  11. SZ Scale the object on the $z$ axis
  12. Add a Solidify modifier, Bevel modifier, another Subdivision modifier:

Whoops, it's not archimedean, you could create a Bezier manually and bevel it with an arc profile, but Geometry Nodes help with this part as well:

Markus von Broady
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  • Ah I see what you are doing, could you explain a bit what the Empty does for the Screw modifier? – DPlayground Sep 05 '23 at 18:17
  • I want to use an archmedian curve as I mentioned, because I want to have a smaller radius of the second rotation. I added another picture. That is the shape that I want, but I need like half a circle. – DPlayground Sep 05 '23 at 18:19
  • @DPlayground the empty marks the vertical line, around which the screw revolves. In my answer the empty is at world origin, so the screw revolves around the world origin. You don't really need the empty, you could instead move the geometry in edit mode, away from the origin… Unfortunately I missed the "archemedian" part, so I'll post geonodes solution – Markus von Broady Sep 05 '23 at 18:23
  • Could you show what you mean with creating a bezier and bevel it with an arc profile? – DPlayground Sep 07 '23 at 09:20
  • Also, I don't have the Set Curve Normal Node. I am working in Blender 3.1.0 - maybe because its an older version? – DPlayground Sep 07 '23 at 09:21
  • @DPlayground the node is available since Blender 3.4 https://blender.stackexchange.com/a/273542/60486 look into the Robin Betts' answer. – Markus von Broady Sep 07 '23 at 09:36