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Power Axis 1.0
To follow these examples your will need to install powerAxis. Instructions for installing are here on the documentation page.
You should now have three buttons together in a group. In the examples below
they are referred to as plugins 1, 2 and 3, where the numbers refer to the
plugins as follows. This should match up with the numbering within your group.
Note that in the demo version, plugin 3 is disabled. The other two are functional.
Plugin 1. Set 'Origin' Position/Rotation to selection
Plugin 2. Use 'Origin' Position/Rotation for axis
Plugin 3. Align selection to 'Origin' Position/Rotation
1. Basic Rotation
This simple example demonstrates a basic problem with Cinema4D's modelling axes, and how to use powerAxis to solve the problem.
The problem is that applying rotations can result in unwanted translations
at the same time, making it dificult to model accurately.
Problem using standard tools.
Start a new project, switch to front view, create a pyramid and make it editable ('C' key).
Switch to polygon mode and select the front face (make sure that 'only select visible elements' is checked).
Now select the rotation tool, and in the coords manager, apply -30 degree
rotation to the 'B' angle. Note how the 'centre' of the
trangle (marked by the axes) has translated.
Now apply +30 degree rotation to the 'B' angle to rotate the face 'back to where it was'.
You'll see that although the face now has its original orientation again, it is in a different position See below.
To see just how far it has moved, create a second pyramid as comparison,
switch to wireframe, and switch to perspective camera, and spin around the
model. E.g. see below:-
This has shown the problem, now we see how to solve it using powerAxis.
Solution using powerAxis
As before, start a new project, switch to front view, create a pyramid and make it editable ('C' key).
Switch to polygon mode and select the front face (make sure that 'only select visible elements' is checked).
Now Shift-Click on plugin 1, or click on "Set 'Origin' Position to Selection" in the plugin menu (these actions are equivalent).
This has now created a NULL object called 'Origin', which has been positioned at the true geometric centre of the selected triangle, oriented to match the world axes. Now Click on plugin 2.
Note that the plugin button has remained pressed in, indicating that the
'Origin' is now being used to specify the modelling axes, and that because
of this Cinema4D's axes have jumped to the location of the 'Origin'.
Again, as before, select the rotation tool, and
in the coords manager, apply -30 degree rotation to the 'B' angle. Note how
the 'centre' of the
trangle (marked by the axes) has remained in the same place, and a pure rotation has been performed without translating.
Now apply a +30 degree rotation
to the 'B' angle and we get back to where we started. If you again add a
duplicate pyramid, and compare the two in wireframe you will find that the
two are co-incident with each other.
Finally, if you Click on Plugin 2 you will toggle the plugin off and return to normal Cinema4D editing.
Note:
In the first step you were asked to shift-click plugin 1 in order
to set the position only for the 'Origin' object. This was so that in both
cases you were rotating around the same axis, to give a fair comparison.
If you repeat the above example but in the first step you simply click on plugin 1
without the shift modifier, then the origin object will take both its position
and orientation from your selection. The orientation used for a polygon selection
is to set the Y axis to the surface normal, and the X axis parallel to one
of the polygons edges. If you repeatedly click on plugin 1 then the
X axis will cycle around the edges in turn, and so you can then rotate the
face around its normal (so it remains in the same plane) or around axes perpendicular
or parallel to any of its edges, simply by rotating around the X, Y or Z
axes.
This next example demonstrates how powerAxis can be used to 'unfold' a model, by rotating parts of a model around its own edges.
Create a default platonic object, make editable ('C'), and select an edge.
Click on plugin 1 to align the 'Origin' object with the edge. (X axis along the edge, Y axis along the edge normal).
Click on plugin 2 to toggle it on so that Cinema4D uses the 'Origin' object for the modelling axis/origin.
Switch to polygon mode, and select the faces that you want to rotate.
Note that the centre of rotation stays where you put it (aligned with the edge), regardless of what your polygon selection is.Now use 'Structure->Edit Surface->Disconect' to seperate this selection from the main mesh.
Select the rotate tool...
...and click-drag on the red X-axes rotation handle to rotate the polygon selection around the edge..
If you want to change the 'hinge' edge, then switch back to edge mode, select a new edge, and click on Plugin 2 to set the 'Origin' object to your new selection.
Carry on playing with this until you've got the hang of it!
3. Constrained Scaling
This is a quick example showing how to do constrained scaling of parts of a model.
Create a cylinder with 9 height segments, 12 rotation segments, make editable.
Create two selection sets corresponding to the two images shown below, each
containing two bands of polygons.
 
Select a single vertex on the edge of the top face and click plugin '1. Set Origin to Selection'.
This creates an 'Origin' object at that location, oriented to match the edge
geometry. (Note that the 'Y' axis of the origin object - indicated in the
viewport by the green line - is aligned with the edge normal rather than
the world axes).
Activate plugin '2. Use Origin for Axis'. This now sets the centre of rotation and scaling to that of 'Origin' object.
Restore the first selection, select extrude ('D'), and in the 'active' tab set offset to zero, then click apply.
Switch to scale mode, disable the X axis (red) and scale the selection down.
Note that the scaling is taking place relative to the position of the 'Origin'
object. Use 'Snapping -> Quantize -> Scale' to help scale by an exact
amount.
Repeat the above two steps for a vertex on the opposite side of the top surface.
Now
select all other faces (select all then deselect the first two selections),
and scale along the Z axis only to flatten the shape. Note that the
orientation of the object relative to the world axes was not important in
any of this, and that the end result has accurate geometry.
Finally. disable plugin '2. Use Origin for Axis' by pressing it again, and C4D will revert to its usual mode.
4. Alignment of Objects (not in demo version)
Create a standard Platonic Object, a Cube, and a Pyramid. Scale the Cube to 40x40x40, and the Pyramid to 100x200x200.
Leave the Platonic as a radius 100 Icosa. Make all the objects editable ('C').
Switch to poly editing mode, and select a face from the Platonic. Use plugin '1. Set Origin to Selection'
to create the 'Origin' object and move it to the centre of the face. Note
that a set of mini axes show the position and orientation.
Note that the red X axis is parallel with one of the face edges, and the
green Y axis is aligned with the face normal. Repeatedly triggering the plugin
will cause the alignment to cycle around the edges, so that you can choose
which edge you want it to be aligned with. In this case we choose the lower
edge.
Now switch to the Cube, and again select a face.
Select plugin '3. Align Selection to Position/Rotation'. The Cube
is now moved and rotated so that the selected face is aligned with the 'Origin'.
The Cube is now resting on the surface of the Platonic object, and is rotationally
aligned with the lower edge - corresponding to the edge we selected for the
red X axis.
Switch back to the Platonic, and select a single vertex. Use plugin '1. Set Origin to Selection'
to set the Origin object to this new position. Again, using it multiple times
will cause it to cycle through different alignments (i.e. X axis aligned
with any of the edges, or Y axis aligned with the vertex normal).
Switch to the Pyramid, and select a vertex.
Again, use plugin '3. Align Selection to Position/Rotation', and the Pyramid object will by aligned with the Platonic object.
The 'Shift' and 'Ctrl'
modifier keys may be used to specify the position and the orientation of
the Origin object independently. For example, when we triggered plugin 1
to set the origin to the single vertex that we had selected, we could have
held down the shift key at the same time. This would then have kept the orientation
of the face we aligned the cube with, but would use the position of the vertex
we have selected.
In this case the results after triggering plugin 3 would be this.
Note that the bottom of the pyramid is parallel with and rotationally aligned with the cube.
Alternatively, the modifiers can be used when triggering plugin 3 'Align
Selection' to update either the position or orientation of the object only.
E.g. If you wanted to rotate an object so that a selected part matched orientation
with the 'Origin' object, but you didn't want to change its position, you
could use Ctrl - plugin 3.
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