Using Quadrupeds in Poser Walk Designer By DAD Software needed: 3D Modeling Program Poser (Tested in P6) EasyPose Underground by Ajax Introduction: The Poser Walk Designer tab is normally used for defining walk patterns for Biped characters. When attempting to use this part of the software package to create a walk design for a quadruped, the results are less than satisfactory as shown in fig 1. Fig 1 This problem is due to the fact that Poser is trying to drive the walk by motivating the rear legs and treating the front legs as if they are a bipeds arms. The main reason that this occurs is due to improper subdivision of the body parts for naming the appendages and the names assigned to the associated joints of those appendages. If the design of the quadruped is approached from the idea that the walk will be driven by the front legs and proper division of the appendages and a different approach to naming the joints is taken, a successful design can be achieved. For this exercise a custom quadruped character is going to be used. But these conventions can actually be applied to existing quadruped Poser content with some success too. I will be using my cartoon Donkey to illustrate the procedures and naming conventions used to create a quadruped that works in the Poser Walk Designer. Part 1: Character Design. When designing a quadruped character for use in Poser that is planned to be used in the Walk Designer, it is best to design the front and rear legs with similar joint angles and separation points. You also need to design both the front and rear legs with the idea that they

will each only have three joints. The joints for each of the legs will be variations on the Thigh, Shin, and Foot as follows: Right Front leg: rThigh, rShin, rFoot Left Front leg: lThigh, lShin, lFoot Right Rear leg: rRThigh, rRShin, rRFoot Left Rear leg: lRThigh, lRShin, lRFoot These naming conventions make it easy to identify which leg is which when working with the character. When the basic design is complete and imported into Poser. The joint hierarchy should look something like this (fig 2): Note that the rThigh and lThigh are attached to chest bone of the hierarchy and the rRThigh and lRThigh are attached to the hip bone of the hierarchy. This structure will allow the front legs to drive the animation of the walk design.

Fig 2 Once this skeletal structure is establish in the Poser character and the joint parameters are set, the character design should look as shown in Fig 3 when set up in the Walk Designer. Initially the hind legs will not move when the character is loaded into the walk Designer but an acceptable front leg movement should be seen at this time. Fig 3

At this point we need to translate the movement of the front legs to the rear legs in a side for side swap to create a simulated walk design for a quadruped. This will be done by establishing master/slave relationships between joints in EasyPose Underground. Step 2: Master/Slave joints. (ERC) I use EasyPose Underground by Ajax to setup and establish the ERC master/slave relationships that are needed between the front legs and the rear legs to translate the Walk Designer animation of the front legs to the rear legs. Close attention needs to be paid while doing the ERC setups because the right front leg joints will be used to translate animation movements to the left rear leg and vice versa for the left front leg/right rear leg. The ERC will be set up using the ERC Dial control section of EasyPose as illustrated in Fig 4. A control ration setting of .5 is used so that only half of the animation movement of the front leg is translated to the rear leg. Anymore than this and the rear foot will intercept the front foot in extreme positions. Fig 4 Each master joint of the front leg must be associated with the slave joint of the rear opposite leg as show in these charts. Right Front Leg

Left Rear Leg

rThigh

lRThigh

xRotate

xRotate

yRotate

yRotate

zRotate

zRotate

Right Front Leg

Left Rear Leg

rShin

lRShin

xRotate

xRotate

yRotate

yRotate

zRotate

zRotate

Right Front Leg

Left Rear Leg

rFoot

lRFoot

xRotate

xRotate

yRotate

yRotate

zRotate

zRotate

Left Front Leg

Right Rear Leg

lThigh

rRThigh

xRotate

xRotate

yRotate

yRotate

zRotate

zRotate

Left Front Leg

Right Rear Leg

lShin

rRShin

xRotate

xRotate

yRotate

yRotate

zRotate

zRotate

Left Front Leg

Right Rear Leg

lFoot

rRFoot

xRotate

xRotate

yRotate

yRotate

zRotate

zRotate

Correct establishment of the master/slave ERC relationships can be verified by looking at the slave liberator section of the ERC Dial Management section of EasyPose as shown in Fig 5.

Fig 5 After saving the modified CR2, you can restart Poser, load the modified character and perform a test animation in the walk designer. The results should be similar to those in the test animations provided with this tutorial. Conclusion: There are know issues involved with this procedure. Since the joints differ slightly from the front to the rear legs there will be small amounts of joint popping. This can be minimized by turning IK on after the walk design has been made. Additionally, modifying the frames where these pops occur can also smooth out the animation. Additionally it will appear that the rear legs float slightly above the ground. This too can be worked on and smoothed out by editing the offending frames manually. But, for basic cartoon style animation, this procedure provides a quick and easy way to get your quadrupeds walking in Poser. It is also a good idea to have a standard version of the model without ERC and a Walk Designer version. This is useful when you want to do a standard pose that does not require the master/slave connection between the front and rear legs used in the Walk Designer. For additional information and questions regarding this tutorial, please feel free to contact me at: [email protected] Written by: David D'Champ (DAD)