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character animation

Character Animation 3: Weight Painting

Once i completed the rigging process i moved onto weight painting.

Weight painting, for me, was quite difficult and I tried a couple ways of weight painting before i fully understood it. The first way was using the weight paint brush, this worked in some areas, however in other areas it didn’t really work well due to multiple layers of the character model, i then began to experiment with vertex weight painting which uses vertices and faces to weight paint. I found the second option so much more helpful as well as easier compared to using the weight paint brush so I decided to stay with this option.

I first began weight painting the arms, I did this as they were the easiest parts to weight paint, I did this by pressing shift + alt to select the faces all around the arm and continued doing this until I got to the boundaries of the upper arm bone. Below is an image of the bone and the weight painting around it.

I did this same tactic with both arms and all the bones in them.

For the lower left arm I entered x-ray mode so see through the mesh and select all faces below the upper arm bone, however I did intrude on the upper arm bone area slightly to give the lower arm more realistic movement when i wanted to bend the elbow.

I did similar to this on the lower left arm, just didn’t include the hands because this arm has a hand contrary to the left hand.

The hands were quite simple to weight paint as I only really needed to attach a small amount of faces to each of the bones.

I moved onto the legs next. They were difficult compared to the arms as there was a lot of over-lap and large surface areas to cover which made me switch between the weight paint brush and face weight painting often for these bones.

Firstly I went with the hip bones, these were the difficult bones that I had to deal with first. These caused problems as the area which I needed to cover was quite big compared to other bones and also was not mostly flat. The problem i faced was that when i put a rough weight paint down they were both connected and the trousers also had multiple layers inside of them which needed to be painted too.

This was a problem as once I began moving the leg as a test the insides of the trousers would move slower and faster than the actual trousers leg itself, and would clip through it, I quickly fixed this by going into x-ray mode and selecting the offending faces and changing the weight value on them, once I did this however I had faces from the opposite leg moving with the leg that I was working on at the time. I fixed this by once again selecting the faces and changing the weight to 0, I then moved the leg to the rest position and it was all fine again.

I moved down the leg to the other bones and didnt have to do too much for them. I first selected the faces i wanted, added a gradiant of weight values and assigned them to the bone, i did this for both the lower thigh bone and also the lower leg bone.

Finally for the legs I moved onto the feet. These both had some issues however they were easily fixed.

The issues were that the lace holders on the shoes didn’t want to be weight painted, however I managed to fix this after a while so that all of the shoe and feet inside the shoes would act properly and not clip out of each other.

Once I finished the legs I went onto the chest which was rather easy to weight paint, all i did was enter x-ray mode select faces that needed to be selected towards the bone boundaries and assign them a medium-higher end colour, around 0.6-0.75 strength. Below are some images that corrospond to this part of the weight painting process.

Finally I moved onto the head and for this I made the entire head the highest strength possible which was one and it would make it bright red. One issue I had while doing this was the eyes. At first i wanted to animate the eyes, however after attempting it I decided not to and joined them to the characters head and weight painted them too.

I had a slight gradient at the bottom towards the clavicle bones and once I did that i completed weight painting.