Axis angle rotations and changing rotation values

[dumb_squared]

I have two 3d applications and when an object(a cube for example) is transferred between them, the rotation values of the cube change(the object stay at the same location. translation and scale values stay the same) and I can't find why that occurs and it's driving me crazy.

app 1 rotation values:

x:-27,077
y:-25,026
z:15,933

Axis-angle representation of the above

-0.7096853 0.4914011 -0.5048483 -42.20802

app 2 rotation values:

x:33.8493041
y:-13.7234678
z:26.2455062

I've read a few wikipedia articles on rotation and specifically axis-rotation stuff but I haven't really figured out what's really happening.

Any help is appreciated.

 

[D H]

You're jumping in a bit to deep, getting to specifics way too early. Before we get to the specifics, there are some key important question that needs to be addressed:

• Are these your applications or are the someone else's? In other words, did you write the code?
• If you didn't write the code, did you carefully read the documentation (if it exists) and follow it?
• If you did write the code, did you carefully test it?
• How does the code represent composite bodies, sub-bodies, and the connections between them?
• Is this transfer is an atomic action, or is it essentially a detachment immediately followed by an attachment? If it's the latter, is it the attachment or detachment where things go awry?

 

[dumb_squared]

You're jumping in a bit to deep, getting to specifics way too early. Before we get to the specifics, there are some key important question that needs to be addressed:

• Are these your applications or are the someone else's? In other words, did you write the code?
• If you didn't write the code, did you carefully read the documentation (if it exists) and follow it?
• If you did write the code, did you carefully test it?
• How does the code represent composite bodies, sub-bodies, and the connections between them?
• Is this transfer is an atomic action, or is it essentially a detachment immediately followed by an attachment? If it's the latter, is it the attachment or detachment where things go awry?

Sorry about lack of clarity. Both applications are closed sourced and there is no information about how they store the data.

The transfer file format converts x,y,z angles to Axis-angle representation

 

[HallsofIvy]

Yes, but what do those angles have to do with a rotation? A single axis of rotation can be given by its three direction angles- the angles the axis makes with the three coordinate axes. Also, if this is the case, x, y, and z are not independent. We must have $x^2+ y^2+ z^2= 1$. Is that what you mean? Where do you give the angle through which you are rotating?

 

[blue_raver22]

I would first suggest checking the coordinate systems and units used in both applications to ensure they are consistent. It is possible that one application is using a different coordinate system or unit of measurement, resulting in different rotation values.

Additionally, it is important to understand that rotations can be represented in different ways, such as Euler angles, quaternion, or axis-angle representation. It is possible that the two applications are using different methods to represent rotations, resulting in different values.

I would also recommend checking the order of rotations applied in each application. The order of rotations can affect the final orientation of an object.

If all of these factors have been accounted for and the rotation values still do not match, it is possible that there is a bug or error in one of the applications. In this case, it would be helpful to reach out to the developers of the applications for further assistance.

Overall, understanding the mathematical principles and concepts behind rotations can help in troubleshooting and understanding why rotation values may differ between applications.