Compute Distance Map

Compute Distance Map

This command will color a region of interest (ROI) on an OBJ file created from DSX with a distance map and calculate the contact point.

Distance maps:

• Each vertex is colored according to its closest distance to the other surface (which can be to a vertex, edge, or triangle of the other surface). Smooth shading is used so that a triangle's color is a linear combination of the colors of its three vertices.

Contact point:

• The overall minimum distance is calculated (_Min)
• The contact path is the weighted minimum distance (_Contact)

Command Output

For every Result Name specified, there will be 6 results: ResultName_SegmentName_Min ResultName_SegmentName_Contact ResultName_SegmentName_Vert

Minimum Distance

The minimum distance between the two segments. This single distance value is calculated for each triangle and is the distance of the smallest value of: (a) the closest of its 3 vertices (b) a vertex on the other surface that projects onto the triangle (top image) (c) an edge on the other surface that projects onto the triangle (bottom image)

Contact Path

The weighted minimum distance between the two segments.

• Once each triangle has been assigned a minimum distance, a preliminary contact point is found by calculating a weighted average of all the triangle centers. Each center is weighted by the triangle's area and the square of its distance. The area threshold percentage indicates the percent of the total number of triangles on the surface to be included in the calculation. Then the weighted contact point is projected onto the surface of the segment (since the averaged point could be above or below the surface of the segment).

Min Vertex Distances

This is the minimum distance value that is used to color each vertex in the OBJ.

Note: Do not click on this signal and open the data view, Visual3D will not be able to open the data view due to the number of columns.

Sign of the Minimum Distance

The sign of the minimum distance (positive or negative) is determined by projecting the distance onto the face, vertex or edge normals (depending on the test). The sign of the projection defines the sign used for the minimum.

Command Dialog

Result Signal Information: Result Type: Derived Result Folder: Result can be stored in any folder Result Name: One result name for each region you are comparing Color Map: Min Color & Value Determines the color for the minimum value All vertices with a minimum distance less than the value specified will have this color Inner Color Specifies the mid color and the gradient Max Color & Value Determines the color for the maximum value All vertices with a maximum distance greater than the value specified will have this color Event Sequence: Without an event sequence the distance map will be created over all frames of data where the segments exist When an event sequence is specified the distance map will only be calculated for the specified frames (can be more time efficient to only analyze the time period of interest) Regions: Segment Names: Specify the name of the segments to be compared Proximal Region & Sub Region: The regions correlate to the regions of interest created in the DSX suite Contact Point Area Threshold

Drawing the Contact Path

You can draw the contact point and it's path on the surface:

Steps

For every Result Name specified, there will be 6 results: ResultName_SegmentName_Contact ResultName_SegmentName_Min ResultName_SegmentName_Vert Right click on the _Min or _Contact to specify the draw properties

Target Size: Size of contact path (small, medium, large or hide) Note: Size of contact path can be modified further by going to Settings -> Modify Scale of the 3D graphics Objects Modify the target size Target Color: Specify the color of the contact point Trails: Specify the color for the contact path and the number of frames before/after the current frame to draw the path Trail thickness specifies the thickness of the path

Camera Settings

The skeleton toggle button on the toolbar turns segment drawings on/off:

• All on
• Kinematic on
• Kinetic on
• All off

You can set one segment to be always drawn by right click on the segment name under Kinetic_Kinematic in the data tree, and selecting "Draw Segment Properties". Check "Draw Segment (Override Visual3D Global Draw)", this means the segment will always be drawn.

You can manually adjust the camera perspective:

• Right Mouse: Zoom in/out
• Left Mouse: Rotation
• Right + Left Mouse: Translate

You can set the camera perspective to lock onto a segment by going to View -> Set Camera Perspective.