Re: Please tell me how to edit motion data captured through motion capture.

hyonche3389 · ‎11-21-2024

Hello, I am a university student from Japan. I am using AI to translate, so my sentences may be a bit awkward. Please bear with me.

For my graduation research, I am currently using MotionBuilder 2025. I plan to import C3D data obtained through optical motion capture, edit the motion data, and create variations of multiple motions.

For example, I want to edit only specific parts of a motion, such as the pose of a punching stance. I understand that using animation layers might allow me to do this, but I’ve noticed that editing one part often affects the subsequent motion. Therefore, I am looking for other methods, such as filters, that might allow more precise adjustments.

(view in My Videos)

In this video, I edited the stance pose, but it caused the subsequent motions to behave strangely. Adjusting the weight of the layers could be one way to address this, but I am struggling with setting up adjustments like:

Frames 0–10: Weight effect = 0
Frames 10–20: Weight effect = 100
Frames 20 and onward: Weight effect = 0
When I try, the effect of the layer still influences frames 0–10, for instance.

(view in My Videos)

I’ve heard that it is possible to set keyframes for the weight, but for some reason, the weight property does not appear in the FCurves panel.
Because of this, I would like to know about alternative methods, such as filters, for making these kinds of adjustments. Additionally, if there are any Japanese resources for editing motion in MotionBuilder, I would appreciate it if you could share them with me for future reference.

I apologize for the lengthy message, but I would be grateful if you could assist me with any part of my questions. Thank you!

Hikaru_T · ‎11-29-2024

Hi there,

I'm also a college student in Japan who works with MotionBuilder. I'm glad to see you in this forum and to learn about your graduation research.

I understand that using animation layers might allow me to do this, but I’ve noticed that editing one part often affects the subsequent motion.

To avoid affecting the subsequent motion when adding keyframes, I always add a zero key on both sides of the additional keyframes. This process helps to prevent unintended changes to your animation data in other layers.

In this video, I edited the stance pose, but it caused the subsequent motions to behave strangely.

Could you please explain in more detail how you edited the stance pose? If you don't mind, please share the motion FBX data.

I’ve heard that it is possible to set keyframes for the weight, but for some reason, the weight property does not appear in the FCurves panel.

To control the weight of an animation layer, select the layer and go to the FCurves tab in the Navigation window. You will see the name of the layer and the "weight" property in the left-side panel. This property is not animated by default, so no function curves will appear in the FCurves panel. By pushing "A" button of the property, you can animate it and add keyframes, so you will be able to control the influence of animation layers using FCurves.

Because of this, I would like to know about alternative methods, such as filters, for making these kinds of adjustments.

I think the Story tool is helpful for editing specific parts of motion. Using the Story window, you can selectively apply motions to destinations and control the animation data by fading, blending, or overriding clips. The Story tool can also import command tracks, allowing you to influence the animation via scripts. You can find a tutorial on the Story tool here: Autodesk MotionBuilder Story Tool Tutorial.

Additionally, if there are any Japanese resources for editing motion in MotionBuilder, I would appreciate it if you could share them with me for future reference.

I have read these resources and they helped me a lot with editing motion data.

I hope these suggestions can provide some direction for your research.

Kind regards,

Hikaru T.