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Contact Point editing

Contact Point editing allows manual adjustment of segments in the Motion Capture data to change any engine defined contact points. Below in this article examples are given of specific situations where Contact Point editing might be useful. 

NOTE: Contact Point editing is typically not necessary if you use the HD reprocessor. Try to use the HD reprocessor before doing Contact Point editing. More information on HD Reprocessing.

 

Snapping of segments

In the originally recorded MVN file, a contact on the midfoot has been wrongly detected. The result is an unlikely position of the foot segment with respect to the lower leg and a discontinuity in the position of the total character. Removing this contact will improve the data.

1. Click on the foot segment. Step forwards and backward in time to identify the wrongly detected or missing contacts.

ContactPointEditing1.jpg

2. Select the identified time frames by clicking the left mouse button. The selected frames will be highlighted. By manually defining a contact point, all other contact points of that frame will be removed including contact points of segments other than selected.

 ContactPointEditing2.jpg

3. To add contact points without removing existing points, hold the shift button when releasing the mouse button. This option should not be used excessively, but maybe useful to optimize discrepancies when two segments make contact at the same time frame.

4. If a wrong frame or contact point is selected, you can undo this by a click on the right mouse button and select ‘Remove user-defined’.

ContactPointEditing3.jpg

5. To remove all contact points such that no segment has contact, click and drag the right mouse button on the desired frames and select ‘Force no detection’. The contact bar will then show a black band.

6. After editing the contact points, press the reprocess button or ‘Ctrl+Shift+P’. The MVN Fusion Engine will now re-compute all kinematics using the original inertial sensor data taking the overruled contact points into account.

Foot slide

In the originally recorded MVN file, the foot is already on the ground but the contact is detected too late. The result is that the character seems to stick at a wrong contact and the foot slides back.
1. Click on the foot segment. Step forwards and backward in time to identify the frames and possible contact points. In this case, the heel (blue sphere) is the most likely contact point to have contact with the ground.
ContactPointEditing4.jpg
2. In the contact bar, select the frames of the heel (upper bar) with the left mouse button. The selected frames will be highlighted.
3. After editing the contact points, press the reprocess button. The MVN Fusion Engine will now re-compute all kinematics based on the overruled contact points.
4. Verify the modified contacts. The red sphere should be enlarged during the selected frames and foot slide should no longer occur during these frames.
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