Building the rig

My previous experiences with rigging haven't been altogether successful, however I decided to give it a go. I created a very simple rig containing enough bones for the movement. When I attached it/enveloped it to the model the movement wasn't working. Creasing and twisting appeared and after researching how to create a more appropriate rig I realised that the built-in Biped Rig in Softimage would probably be the better option.

The rig on the left shows how it originally looked before I altered it to fit my model. The one on the right has been scaled down to fit the body parts of my panda model. All the separate pieces had to scaled down individually or it caused problems with the movement later on.

This shows the rig actually placed inside of the panda model. I had to scale down the neck sections as Hamish doesn't really have a neck, the part above that connects to the head control had to be placed higher up and the shoulders had to be adjusted slightly. I extended to spine because i designed him to be out of proportion, this was so he could have smaller, stubby legs and waddle rather than walk normally to compensate for his large stomach. I moved the waist control slightly down and put the hip control slightly above, this creates a nice movement in his stomach when he walks forwards.

Now that the rig is properly set up and adjusted to fit the model, I needed to start the enveloping process. Straight away I noticed that the legs were proving difficult, When i moved the model or the top of the leg controls I was getting strange creasing and twisting.

When I attached the model to the rig by enveloping it, the weighting of it was far away from what I needed it to be. To fix this I had to use weight painting in order to tell which points on the model to be controlled by which bones/controls. I had a major problem with this as some of the points where being controlled 100% by a bone and wouldn't connect to another bone, to fix this I had to choose the 'reassign locally' option, then make sure all bones and controls were showing by clicking 'show all'. I had to find the point number in the table and move the sliders needed across.

The neck section of the model worked surprisingly well, even though he doesn't really appear to have a neck I still want it to look like he has one, be it hidden, to create this affect I allowed some of the points in his chest to move when his head is rotated.

For the eyes I originally thought that I could control them by rotating the top eyelid, the bottom eyelid and the actual eyeball individually but after a quick test it was too difficult and time consuming to continue with it. After a bit of research I realised I could control it using a 'link with command' option, this links each individual rotation of the eye objects to a relative value in the Y axis of the curve controls. It means that I can use the position of a null or a curve to control the movement of a particular object/model. I am using the transition of two circle curves to control the shutting of the top and bottom eyelids on both eyes, then the rotation of a square curve to control the movement of the eyeballs.

After I had finished fixing the eyes I went back to the rig. It still needed tweaking so that when he bent forwards or slightly backwards there wasn't any creasing, I also hid the parts of the rig that I won't be using to save later confusion.

Continuing on from tidying up the rig and hiding any bones or parts that I won't be using to control my rig, I decided to use shadow bones to help. You can re position them outside of the model and you can use a different shape to make them easier to select. I decided to use rectangles and cubes as they still represent the size of the bones.

Most areas of the rig are now complete but I am still having problems with the legs. The back of the feet are creasing together, the stomach is moving too much when the leg is lifted and the foot stretches away from the leg. I tried to use weight painting to fix this problem but I was still having issues with it.

The main reason for the odd movement with the legs I believe is because I couldn't use the bones to rotate the legs and feet. I tried to rearrange the rig slightly to compensate the movement but in the end i deleted the original parts for the legs and built my own. I used a simple two bone tier, one for control the leg and the other to allow the foot to bend.

I'm now thinking that adding an extra bone to create a knee might make the movement more believable. At the moment he is waddling slightly, which is the look I was going for but I think it's too obvious.