Monday, 12 May 2014

Rigging Issues with the Spider Mech

On top of the main WoSD, I was also assigned with the task of rigging and texturing Adam's spider mech model. The original concept came from a painting produced by Adam in the R&D phase. With the deadline creeping up, we have accepted the strong likelihood that we will only be able to complete one playable level. The Spider Mech model was created early on, and Adam had the idea of including it as a SOI machine highjacked by the Marauders. This way the SOI lore is still present within the Marauder game level. The stolen Spider Mechs are owned by the 'Nasti Moon' clan,  who adopt a yellow colour scheme:

There is a conscious decision whenever a Marauder clan emblem is drawn to do it loosely freehand. It gives this quickly painted on look fitting the Marauder's chaotic character traits. The Marauder Spider Mech includes also a wooden beer cask, fitting with a new narrative where the Marauders have turned the city into a giant make shift brewery. On this barrel you see the Nasti Moon's clan emblem.

The rig itself for the spider mech was fairly straight forward, using single Ik handles with the standard three joint humanlike legs:

I hit trouble when painting out the influence of the legs on the body of the spider mech. I quickly discovered that I needed to physically hide the legs as to not paint out the influence on them when trying to get to the body. I had the leg meshes on a separate hidden layer originally. The major issue however was that Maya kept crashing when painting out the influence. I researched the issue online and made some attempts to put less strain on Maya when painting the mesh. Firstly I went into the preferences and deactivated the undo feature so that Maya was no longer trying to remember 50 stages while using the 'paint skin weights' tool. Secondly, I toggled off the 'construction history' feature:

Unfortunately this didn't resolve the issue, and I kept getting error messages. The only solution was to reduce the size of the brush and paint carefully, trying not to influence too many vertices at once, and to save very regularly. On reflection, we are working with very simple low poly models, so the weight painting shouldn't have really caused problems. Speaking with tutor Matt, he explained how others had reported similar struggles when weight painting in the Maya 2014, and that could be accredited to a bug. Unfortunately this glitch made the process much more drawn out than it had to be, causing me to have to boot up Maya and reload the scene repeatedly after a crash.

Matt also noticed an issue with the weight painting of the legs:

Notice how the influence from the knee joint is causing the end of the first leg mesh to bend up. I realised that I needed influence running down the leg mesh from the leg joint, and same with knee mesh and knee joint, as shown below:

The gradient mode also shows blue influence on other legs, and there was also some unwanted influence affecting the front of the body and the wheels. Rhys offered to complete the weightpainting before resuming his role as animator. This is where good practice and naming conventions were important with the rig enabling Rhys to navigate around the model and work efficiently. 

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