Few days back I got an email from a friend asking me for a method to stretch the arm with global scaling without using any scripting.
Here is a quick way to do it:
1/ I created a basic IK arm rig, nothing fancy.
Here is a quick way to do it:
1/ I created a basic IK arm rig, nothing fancy.
2/ I used the Distance tool(Create-Measure Tools-Distance Tool) to measure the distance between shoulder and wrist. Snap the start and end locator to shoulder joint and wrist joint respectively. Point constraint the l_armDistStart_loc to the l_shoulder_bn and l_armDistEnd_loc to the l_arm_ctrl.
A distance node is created and you can find the distance value in the shape node of the distance node.
3/Open the node editor, and add the Global_ctrl to it; create a multiply divide node and rename it to GlobalArmScaleMult_nd. Connect the Global_ctrl.scaleY to GlobalArmScaleMult_nd.input1X and the operation is meant to be Multiply.
As my arm is slightly bend in the default pose, I need to straighten it before it starts stretching, that is the total distance I need to note before I apply stretching. Copy the distance value and paste it in GlobalArmScaleMult_nd.input2X.
4/Add distance shape node to the node editor and create another multiply divide node; rename this node to l_armStretchDiv_nd. Here we will divide the distance value with outputX value of the GlobalArmScaleMult_nd.
5/As this is an arm, we aren't going to squash it. We need to keep the scale value 1 if the distance between Shoulder and wrist gets less. To do this, we will add a condition node. Create a condition node and link the outputX value of the l_armStretchDiv_nd to the first term; check if it is greater than or equal to one which means the distance has increased(the control has been stretched). If true, hook the value of l_armStretchDiv_nd .outputX else leave the value to 1.
6/We are almost there, all you need to do it connect the outputX value of the condition node to the l_shoulder_bn.scaleX and l_elbow_bn.scaleX.
Tadaaa!! All done :D
