polar Coordinates

The plane the radius is measured on is defined by the axial component of
the three coords; which are a) radius ( perpendicular to the axis of
rotation),b) angle in the plane of the radius, c) and distance of the
plane from the origin,measured along the axis through the origin.

Then I would select a ring of points at the same r and z, and change
either or both of the r & z values.

My initial idea of using the torus was to generate a tyre/wheel assy.

I thought I might be able to edit the cross-section to more accurately
simulate the tyre sidewall and wheelrim. It appears that this method
will not work.

Your last paragraph is right - I will have to generate the tyre section
profile  as a curve, and extrude it around a circle. The same goes for
the wheel rim,etc.

Which brings me to a further question.

With the extrusion of the tyre section around a curve, I would expect
the extruded shape to change if I edited the section profile, since the
extruded shape is the child of the section curve.

However,when I am constructing my car body by using the series of
profiles as formers for the skinning process, I find any changes to the
shape of the formers after skinning do not affect the existing skin, and
I have to delete the skin and create another skin on the modified formers.

How can I make the skin conform to the formers ,if the formers are
modified after skinning?

On 29/04/2020 19:27, Luke S wrote:

I feel like we're talking about two different things here

It would ease editing rings of points - ie select specific ring ,
and input new radius.

Keep in mind, AOI is not 'CAD' per se. It's more focused on modeling
from an art/rendering perspective.

I could /maybe/ see a tool for that specific use case, but it would be
niche - an add on. Plus, it leads to questions for implementing:

• What plane is the radius measured on? Based on the view direction?
  Maximize existing radius? Something else?
• Are you trying to force all points in the ring to the same radius,
  or are you scaling their radius compared to current positions?

---

I'm not sure what the above has to do with a toroidal mesh, though. I
think the closest to what you (Seem to be) trying to do is to create a
closed curve, (Probably use the |Create Polygon| tool) and then
generate a tube object. You can scale this object without changing the
cross-section of the tube.

---

[feature-requests:#390]
https://sourceforge.net/p/aoi/feature-requests/390/ polar Coordinates

Status: open
Group:
Created: Tue Apr 28, 2020 01:22 PM UTC by Bob Haigh
Last Updated: Wed Apr 29, 2020 11:55 AM UTC
Owner: nobody

I created a toroidal mesh . It appeared as an ellipse with variable
thickness ie cross-sectional dia.
I don't know why the thickness is not uniform, but if there were a
polar coordinate option at least I'd be able to edit the points to
return the toroid to a circular ring with uniform thickness.
Is it a major exercise to introduce polar coords?

---

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Thanks for this most crucial information, particularly about the
Polymesh and Join Objects.I will investigate those tools.

re Mirroring, I was thinking along those lines late last night, thanks
for confirmation.

On 30/04/2020 01:30, Luke S wrote:

The plane the radius is measured on is defined by the axial
component of the three coords; which are a) radius ( perpendicular
to the axis of rotation),b) angle in the plane of the radius, c)
and distance of the plane from the origin,measured along the axis
through the origin.

Ahh... You are thinking in terms of an actual ring primitive. I was
thinking in terms of "Select vertices from this mesh and treat them as
a ring"

With the extrusion of the tyre section around a curve, I would
expect the extruded shape to change if I edited the section
profile, since /the extruded shape is the child of the section curve./

No, it's not. It is an independent object. There is no such thing as
an "Extruded Object" or "Skinned Object" type in AOI. They are both
merely Spline Meshes, constructed using the curves as a reference. For
a while, now, I've been considering adding some visual feedback in the
object list to show what type an object is, but today is not that day.

How can I make the skin conform to the formers ,if the formers are
modified after skinning?

Edit the Spline mesh, if the changes are localized. Re-Generate from
new curves if the form-curves are being changed and imported from
elsewhere.

Mirror function?

Unfortunately, this is an are where AOI is a little lacking at the
moment. The process I would use:

• Duplicate the spline surface (Just select the object, then Copy &
  then Paste)
• Open the second copy for editing
  o Select all vertices
  o Mesh->Transform (Fill in scale -1 for the appropriate axis)
• Combine using |Join Objects| script (available through the plugin
  manager. It's a tool plugin)

Alternatively, you could convert to a polymesh (Need |Polymesh|
plugin, also available through the manager) Which has built-in mirror
modeling.

---

[feature-requests:#390]
https://sourceforge.net/p/aoi/feature-requests/390/ polar Coordinates

Status: open
Group:
Created: Tue Apr 28, 2020 01:22 PM UTC by Bob Haigh
Last Updated: Wed Apr 29, 2020 10:05 PM UTC
Owner: nobody

I created a toroidal mesh . It appeared as an ellipse with variable
thickness ie cross-sectional dia.
I don't know why the thickness is not uniform, but if there were a
polar coordinate option at least I'd be able to edit the points to
return the toroid to a circular ring with uniform thickness.
Is it a major exercise to introduce polar coords?

---

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https://sourceforge.net/p/aoi/feature-requests/390/

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