Mel - Keyframe & Expression Animation

Mel
Keyframe & Expression Animation

Introduction

This tutorial provides mel scripts that demonstrate the general principles of using keyframes and expressions for animation. The object that is animated in listings 1 and 2 is created by the ring() procedure that was introduced in the tutorial "Mel: Modeling with Smart Transforms".

Figure 1

Listing 1 (keyframe.mel)

source "FULL_PATH/ring.mel";
select -all;
delete;
  
// Get the "master" object
ring(5, 4);
 
for($i = 0; $i < 5; $i++)
    {
    string $temp[] = `instance -st`;
        
    //_____ keyframing _________________
    currentTime 1;
    xform -os -t 0 0 0; // <<<--- IMPORTANT
    setKeyframe ($temp[0] + ".translate");
    
    currentTime 30;
    xform -os -t 0 $i 0;
    setKeyframe ($temp[0] + ".translate");
    //__________________________________
    }
  
playbackOptions -min 1 -max 30;
//play;

Listing 2 (expression.mel)

source "FULL_PATH/ring.mel";
select -all;
delete;
  
string $exp = "";
int    $fcount = 30;
  
// Get the "master" object
ring(5, 4);
  
for($i = 0; $i < 5; $i++)
    {
    string $temp[] = `instance -st`;
    //_____ expression _________________
    $exp += $temp[0] + ".translateY = ((frame - 1) * " +
            $i + "/" + $fcount + ");\n";
    //__________________________________
    }
expression -s $exp -ae 1;
// print the expression
//print($exp + "--------------------\n");
  
playbackOptions -min 1 -max $fcount;
//play;

Mel Keyframe & Expression Animation

Introduction

Mel
Keyframe & Expression Animation