Anim8or Community

cooldude234,

Whenever I have tried to determine whether a line segment (like an edge) intersects a polygon, I have done it in two steps:
1) determine if and where the line segment intersects the plane of the polygon
2) determine if that intersection is actually inside the polygon

It is unclear from your code segment what Ray1 and Ray2 actually are, but if they are points that define a line segment, then this is how I would solve this problem:


   facenormal=normalize(crossproduct(vert3-vert2,vert2-vert1))   //get normal of polygon plane
   rayvector= ray2 - ray1                                        //get vector of ray line segment
        ray_plane_angle=dot(facenormal,rayvector) //actually the arccos of the angle between
        if ray_plane_angle != 0                   //if zero, the two are parallel
            ray_plane_intersection_point = ray2 + ((dot(vert1 - ray2,facenormal) / ray_plane_angle) * rayvector
            //above, calculate the intersection point of vector of the line segment and plane
            //next add angles of intersection point to two of the vertices at a time.
            //if the angles add to 360 deg (or 2*pi rad) then inside, otherwise the intersection point is outside
            total_angles= acos(dot(normalize(vert1-ray_plane_intersection_point),normalize(vert2-ray_plane_intersection_point)))
                         +acos(dot(normalize(vert2-ray_plane_intersection_point),normalize(vert3-ray_plane_intersection_point)))
                         +acos(dot(normalize(vert3-ray_plane_intersection_point),normalize(vert1-ray_plane_intersection_point)))
            if (abs(total_angles - 2*pi) < 0.001) contact_point=ray_plane_intersection_point

If you are actually dealing with a line segment, rather than an endless line, then you need to check whether the intersection point is actually between ray2 and ray1:
           
            if length(ray2-ray_plane_intersection_point)+length(ray1-ray_plane_intersection_point) > length(ray2-ray1)
                //intersection point is not between ray2 and ray1


I wrote the code in pseudo code rather than a particular language.
I hope that helps.
NickE

Raxx,
The file write ability has many, many more uses than just passing parameters (like writing entire an8 files), plus setting an attribute is not going to let you pass anything large like arrays. 

An object script controller would be a scene controller like position, orientation, or morph, but allow one to run object scripts while in scene mode where the object script would have access to scene mode variables like time or frame and access to the other scene's objects controllers.  I have written fluid simulation and other "physics" scripts that run in object mode.  To use them in scene mode requires quite the workaround to render them.  Please see this thread:

http://www.anim8or.com/smf/index.php?topic=2358.msg17352#msg17352

NickE

A user (Daniel) found a set of BVH files that could not be converted with the current version.  Those files had 6 channels for each bone as opposed to the normal 3 channels.  It was causing the program to crash.  An updated version is attached.

Feedback is appreciated.

You touched me.  I love the poetry, and the presentation was world class!  Go professional.  You have a promising career ahead of you.

Neirao,
Below is your code with the changes you requested:
/*
  *Name: Aling points to (x,y,z)
  *CopyLeft: 2010
  *Author: Neirão
  *Date: 03/03/10
  *Description: based in Vytautas_alinhar_pontos_line_points_v1
  *Parameters:  *= width;  *= height;  *= width_divisions;  *= height_divisions;
  */

/***** Init *****/
#command("object");
object $object;
shape $shapes[0];
shape $shape;
int $shape_count;
point3 $points[0];
point3 $point;
int $point_count;
int $i;
int $j;
int $direction;

/* added by NickE */
point3 $sel_max,$sel_min,$sel_center;

/* end of added by NickE */

if (GUI.Xenabled) $direction = 0;
else if (GUI.Yenabled) $direction = 1;
else $direction = 2;

if (GUI.Xenabled && GUI.Yenabled && GUI.Zenabled) $direction = 3;

meshdata $mesh_data;
$object = project.curObject;
$shape_count = $object.GetShapes($shapes);

/*** Get all selected points from all the shapes ***/

for $i = 0 to $shape_count - 1 do{
$shape = $shapes[$i];

/* If shape is a mesh.. */
if($shape.GetKind() == SHAPE_KIND_MESH){

/* i try this..but dont work.. :( --> || $shape.GetKind() == SHAPE_KIND_SUBDIVISION */

/* Get the shape point number */
$point_count = $shape.GetNumPoints();

/* added by NickE */

        $sel_max=(-10000,-10000,-10000);
        $sel_min=( 10000, 10000, 10000);

        for $j = 0 to $point_count - 1 do
        {
           if ($shape.GetPointSelected($j))
           {
              $point = $shape.GetPoint($j);
              if ($point.x > $sel_max.x) $sel_max.x = $point.x;
              if ($point.y > $sel_max.y) $sel_max.y = $point.y;
              if ($point.z > $sel_max.z) $sel_max.z = $point.z;
              if ($point.x < $sel_min.x) $sel_min.x = $point.x;
              if ($point.y < $sel_min.y) $sel_min.y = $point.y;
              if ($point.z < $sel_min.z) $sel_min.z = $point.z;
           }
        }
        $sel_center.x=($sel_max.x + $sel_min.x)/2.0;       
        $sel_center.y=($sel_max.y + $sel_min.y)/2.0;       
        $sel_center.z=($sel_max.z + $sel_min.z)/2.0;
/* End of added by Nick E */       
 
for $j = 0 to $point_count - 1 do{
if($shape.GetPointSelected($j)) {
$point = $shape.GetPoint($j);
if($direction == 0){
/* $point.x = 0; */
                        $point.x = $sel_center.x;   /* Added by NickE */
}
if($direction == 1){
/* $point.y = 0; */
                        $point.y = $sel_center.y;   /* Added by NickE */
}
if($direction == 2){
/* $point.z = 0; */
                        $point.z = $sel_center.z;   /* Added by NickE */
}
/* TODOS XYZ ATIVADOS alinha todos para  */
if($direction == 3){
$point.x = 0;
$point.y = 0;
$point.z = 0;
}
$shape.SetPoint($j, $point);
}
}
}
}

Some things to think about:
1) Do you really want the center, or do you really want the average?
2) This script works on the actual coordinates of the points, so if a mesh is moved or rotated, it still operating on the underlying point coordinates rather than the transformed coordinates.  This may give different results than what is expected.

Attached below is a working BVH file import program for Anim8or.  For those that are not familiar, BVH is a motion capture file format that describes a skeleton made up of joints (points) and a timeline of XYZ Euler angles that describe the rotation of the joints.  See http://www.cs.wisc.edu/graphics/Courses/cs-838-1999/Jeff/BVH.html for an overview of the description.

Anim8or differs widely from the BVH file format in that Anim8or's Figure Mode uses bones for the skeleton where the orientation of the bones is described by a quaternion.  The Sequence Mode uses XYZ Euler angles to describe the change in orientation of the bone relative to the initial orientation of the bone set in Figure Mode.  In Anim8or, the rotation of the bones, when unconstrained, goes from -360 to +360 degrees.  Conversion to and from quaternions and Euler angles requires the use of trigonometric functions.  The atan2 function, for example, goes from -180 to 180 degrees.  A small change in angle in the BVH file across one of these trigonometric limits can trigger Anim8or to flip the bone 180 degrees.

Anim8or has bugs in calculating the frames between keys.  Sometimes it will interpolate wildly. 

Scene Mode has a bug (or maybe it is intentional) where the root bone orientation is completely ignored.  Since the root bone orientation is the orientation of the entire figure, the bug is overcome by keying the root bone orientation into the orientation controller of the figure in Scene Mode.

Sequence Mode has no translational motion abilities, so the BVH translation is keyed into the position controller of the figure in Scene Mode.

The program can currently read in a BVH file and create an Anim8or project file (an8).  This means it generates a skeleton in Figure Mode, a sequence that uses the skeleton, and a scene containing the figure and the sequence.  It keys the orientation and position for the figure directly in scene mode.  For reference, the program also generates a simple line object in the same position as the skeleton.  I found this useful for getting the size and posture of the object to be skinned close.

BVH files sometimes have issues as well.  Most of the Carnegie-Mellon BVH repository files have zero-offset joints.  This introduces some small error when these zero-offset joints have rotations.  Many BVH files have skeletons of very small scale.  I have added a scaling function to the program to allow you to modify the overall scale of the skeleton.  Many of the BVH file have frames-per-second (FPS) of 30, 60, or 120.  I have added the ability to change the FPS.  Please realize that the recalculation of the FPS requires computational interpolation of the motion.  I am using simple linear interpolation in that calculation that introduces some error.  To reduce the number of keys (to reduce file loading time), the program allows you to choose how often to key the original motion as well as put in a tolerance factor to not key when there is change less than this tolerance factor.  In BVH files that have a lot of fast motion, you will need to key more often.  One martial arts BVH file I tested required every frame to be keyed or significant motion error occurred.  Loading that 650 frame Anim8or file takes about 4 minutes on my computer.  Some BVH files have a first frame that is zero motion (original skeleton pose).  There is an option in the program to skip this frame in the sequence and scene.

Some minor tweaking in Anim8or is often necessary due to the fact that trigonometric functions change rapidly near the limits.  This relatively easy to do.  A BVH file I tested that had a runner turning a 90 degree turn worked fine except the right upper arm was slightly off.  A small adjustment in Figure Mode was all that was necessary.

While the program works pretty well for what it does, the results of the program are not readily portable or incorporated into existing projects.  The final product is in Scene Mode.

The program is written in VB6, so you might need to download some runtime libraries if your computer does not already have them.

Please play with the program and give me your feedback and ideas on how to make this more useful to Anim8or users.

Some hasty examples done with figures from BobIt's figure plugin are posted on youtube:

Chinese Martial Arts:  youtube.com/watch?v=KG9hBBvjoDo[/youtube]]http://www.

Hooker Walk: youtube.com/watch?v=3_AjJkl6qzk[/youtube]]http://www.

Thank you.

Here's the first one I started working on:

A quiet night at the alien lockup:

I will contribute to this project.  Thanks for organizing it.