@zipit Hello, thank you again for your help!

You're right: the objects wouldn't be topologically aligned.

I will have a look into the math you provided here, but I don't understand what the other user choice options would be or what determines an object as being "x_source" or "y_target." I couldn't get it working.

In the meantime, I'm going to look into the solutions you proposed in your testing-the-script.c4d file again. Thank you

@zipit That is very kind of you to revisit this topic, thank you! Also, very cool gizmos

I have considered allowing the user to choose how the axes are different themselves as you have in your example, but I really want to see if calculating the delta is possible first. The reason is that there could be many left & right object pairs to be mirrored that have different axis orientations. Can you think of any way to do this?

For example, this is what I have tried:

• L_Cube's, local rotation is (45°, 0°, 0°). Save this matrix, reset the rotation to (0°,0°,0°) locally, and get the global rotation (-90°, 180°, 0°). We save this matrix and reset back to (45°, 0°, 0°).
• R_Cube's, local rotation is (0°, 45°, 0°). Save this matrix, reset the rotation to (0°,0°,0°) locally, and get the global rotation (90°, 0°, 0°). We save this matrix and reset back to (0°, 45°, 0°).
• Mirror the values using your code
• How can we then apply our global rotations that we got when the objects were reset: (-90°, 180°, 0°) and (90°, 0°, 0°) as corrections respectively?
• In other words, how do we determine the inverted_result_axis and target_adjustment_rotation from your code based on these values?

Here is what I have tried:

    l_diff_x = utils.Rad((-90+90)) #difference between x-axes
    l_diff_y = utils.Rad((180-0)) #difference between y-axes
    l_diff_z = utils.Rad((0-0)) #difference between z-axes

    r_diff_x = utils.Rad((90-90)) #difference between x-axes
    r_diff_y = utils.Rad((0-180)) #difference between y-axes
    r_diff_z = utils.Rad((0-0)) #difference between z-axes

    l_correction = utils.MatrixRotX(l_diff_x)
    l_correction = utils.MatrixRotY(l_diff_y)
    l_correction = utils.MatrixRotZ(l_diff_z)

    r_correction = utils.MatrixRotX(r_diff_x)
    r_correction = utils.MatrixRotY(r_diff_y)
    r_correction = utils.MatrixRotZ(r_diff_z)
    
    l_cube.SetMg(l_reflection * l_correction)
    r_cube.SetMg(r_reflection * r_correction)

This makes sense to me but it doesn't work. There is something missing...putting the corrections into the objects' frames, or inverting them. I don't know; I have tried them to no avail.

Thank you!

@r_gigante Okay, thank you for the reply.

Hi @r_gigante ,
I am still working on this problem every day and could really use some help before the weekend if it's possible.

I think I could just use help knowing how to get the difference between the axes in their default state. Could you please give me some advice on how to go about this? I am trying to apply the different axes' rotations to the mirrored matrices from @r_gigante 's code.

Can you help me to get the right axis rotation values to apply to the mirrored values? Any help would be huge so I don't spin my wheels on this problem for another weekend. Thank you!

@r_gigante Hi Riccardo! Thank you for your reply and for taking a look at the file. I understand about this being a busy time of year. I appreciate the support you and your team gives year-round. It's a special and well-appreciated service that you all provide, thank you!

I think I have the problem narrowed down to one issue: can you offer any code help for determining & applying the axes' rotational differences to the mirrored values when they are at 0 values in position & rotation please?

@r_gigante Hi Riccardo! I'm very happy to get your input into this matter and thank you for the mirroring code at its essence.

There is a major part of my issue that I'm still unsure how to resolve, however: even though it is useful to switch the mirroring plane to ZY, XY, XZ, I'm not able to mirror objects whose axes are inverted. This is common with character rigs so I need to account for it. I mention the Mirror Tool because it has Axes controls. I don't know how to do the matrix transformations for the differing axes along with the Mirror Plane and could really use your help.

While the original code works when the axes are the same, using the mirroring technique with the provided code flips the objects in Y and continually adds to their P rotation values. The rig is using X+ controls with XYZ rotation order. I've included these controls as Scenario 2 in the attached scene file, along with other axis orientations & rotation orders one might see in a rig:
Mirroring Different Axes.c4d

How can I account for the rotated axes? Thank you.

I have been looking at my plugins and my biggest question so far is how to handle urllib2 in a way that will work with both Python 2.7 and 3.7.7. Everything else just seems to be adding parentheses to print functions.

I found this Cheat Sheet: Writing Python 2-3 compatible code that suggests:

# Python 2 and 3: easiest option
from future.standard_library import install_aliases
install_aliases()

from urllib.parse import urlparse, urlencode
from urllib.request import urlopen, Request
from urllib.error import HTTPError

However, trying that in Cinema 4D threw this error:

ImportError: No module named future.standard_library

Fortunately, there are some alternatives to try, like

# Python 2 and 3: alternative 4
try:
    from urllib.parse import urlparse, urlencode
    from urllib.request import urlopen, Request
    from urllib.error import HTTPError
except ImportError:
    from urlparse import urlparse
    from urllib import urlencode
    from urllib2 import urlopen, Request, HTTPError

From that article: "urllib is the hardest module to use from Python 2/3 compatible code."

"If developers have predominately used Cinema 4D's API the changes should be minor, and most changes can be made in a backwards-compatible way so there's no need to maintain a separate code base to continue supporting older Cinema 4D releases. In fact, the 2to3 tool included in every Python distribution makes it easy to identify compatibility issues and can directly patch your code."

Will there be an example of how to do this in the SDK examples on GitHub?

For those who didn't see the announcement this morning, the next release of Cinema 4D is moving to Python 3.7.7
CELEBRATING 10 YEARS OF PYTHON IN CINEMA 4D WITH A MAJOR MILESTONE