[Request] Transformation rotation for animation help

[tomasz]

@chrisglasier said:

My idea is to kind of sneak up on namesets from the rear, as opposed to previous full frontal assault!

[Jim]

@chrisglasier said:

Can anyone help me to translate the x-, y- and zaxis results to degrees for each axis?

Vector3d.angle_between will get you part of the way there.

angle = t.zaxis.angle_between(Z_AXIS).degrees

However, angle_between always gives a result between 0 and 180 (or more accurately between zero and π).

[thomthom]

@jim said:

> angle = t.zaxis.angle_between(Z_AXIS).degrees
> 

However, angle_between always gives a result between 0 and 180 (or more accurately between zero and π).

What..?! All you need to do to convert radians to degrees is appending .degrees? doh!

[Jim]

@thomthom said:

What..?! All you need to do to convert radians to degrees is appending .degrees? doh!

Heh, see the Numeric documentation for the SketchUp-specific additions.

[thomthom]

@jim said:

@thomthom said:

What..?! All you need to do to convert radians to degrees is appending .degrees? doh!

Heh, see the Numeric documentation for the SketchUp-specific additions.

Meh,... I've seen that page, taking note of the unit conversion, but completely missed the ones relating to radians and degrees. goes of to clean up some scripts...

[chrisglasier]

@jim said:

> angle = t.zaxis.angle_between(Z_AXIS).degrees
> 

However, angle_between always gives a result between 0 and 180 (or more accurately between zero and π).

A quick pre-dinner try I get this with 90 deg rotation around X :

Now off to eat!

Chris

[chrisglasier]

@chrisglasier said:

@jim said:

> > angle = t.zaxis.angle_between(Z_AXIS).degrees
> > 

However, angle_between always gives a result between 0 and 180 (or more accurately between zero and π).

A quick pre-dinner try ...

... failed because I made
t = selection.transformation, when it should be something related to vector3D ??
Also I don't understand the difference/relationship/source of zaxis and (Z_AXIS).

Perhaps I have made it too confusing both here and also in this previous topic.

All I want to do is iterate through model entities to make each component and group a javascript array element, each with its own array of name/value couplets at least for xPos, yPos, zPos, xRot, yRot, zRot. The xyz business seems OK, where in an animation, for example, I can compare one entity's position with a new position to determine the translation. I want to do the same with rotations around each of the axes.

Sorry if I'm being rather painful, but I am sure a good result will help the mantra below.

Chris

[Jim]

Chris,

Z_AXIS, X_AXIS, and Y_AXIS are constants that are the vectors of SketchUp's global axes.

Here's a screenshot of a cube rotated 45 deg around the Z axis.

And I just noticed I said to use .degrees in an earlier post, sorry; it's .radians.

---

[chrisglasier]

@jim said:

Chris,

Z_AXIS, X_AXIS, and Y_AXIS are constants that are the vectors of SketchUp's global axes.

Here's a screenshot of a cube rotated 45 deg around the Z axis.

And I just noticed I said to use .degrees in an earlier post, sorry; it's .radians.

Jim I think the fog maybe clearing ... many thanks ... chris

[chrisglasier]

I made a skp, rb, html set to test what I understand so far about transformations on a 3x4x5 metre group. If you want to try it out temporarily unzip the files to your plugin directory.

transformations.zip

Here is a clip of it showing a group rotating around each of the axes in turn:

[flash=425,344:32q3oq38]http://www.youtube.com/v/aXxkHu7gSv4[/flash:32q3oq38]

The rotations are made with:

tr = Geom::Transformation.rotation(Geom::Point3d.new(ent.bounds.center), rv, theDegrees), where rv is the axis,

and the angle_between values with:

(t.xaxis.angle_between X_AXIS).radians

• same for y and z.

From this, I gather if the angle_between values returned are 0-180-180, the group has been turned by 180 deg on the X_AXIS; and if 0_90_90, the group could have been turned 90 or 270 (-90) degs on the X_AXIS; and the same for the angle_between values for the other axis rotations.

The second clip shows the application of different series of rotations:

[flash=425,344:32q3oq38]http://www.youtube.com/v/TFAnDrHXaIg[/flash:32q3oq38]

Screenshots of rotations providing angle_between values of 90-90-90 shows there is either something fundamental missing or perhaps that an entirely different method is appropriate.

Any suggestions about this most welcome...

Chris