Thursday, 8 May 2014

Game Art and Machinima: Weight Painting Problems and Solution

By Meg Sugden

When testing my platypus model in Unity I found that we had encountered a few problems. I first just wanted to test to see if the model had gone in correctly, which it had and I really liked the look of it.


I then tried to move the pose of the platypus so that I could see if it was moving correctly and this is where I found my problem. There was something wrong with the influence of the weight painting on the legs/feet of the platypus so I had a look at another version of the model, this time in the crawl position, to see if it was still an issue there, which it was. 



Therefore, as I had previously been exporting as an FBX I tried doing it as an original FBX DAE export instead to see if this would fix the problem as it can help cancel out unnecessary commands in the history of the model, but this only made it worse.


Therefore after consulting with a tutor about what to do to fix this problem she suggested that there was definitely some problems with the weight painting in the feet/legs. I thought this too seen as the top half of the model appears to be fine. So what I thought would be best is to do the weight painting again in the feet. The problem with this, as told by my tutor is that there could be a problem during the initial weight painting and binding so suggested that I should go back to the pre-bind stage and then do this process again to ensure that there is nothing wrong with it. As I knew that I didn't have a lot of time left I wanted to do this as quick as I could, ensuring that everything has been done correctly and without any issues.


After some time Stuart eventually thought he found the solution, which was that we had smooth binded the model too early in the rigging process and this created too many vertices that were hidden inside the geometry and therefore was not effected by the weight painting as these were not being affected. Unfortunately we did not have an earlier save of the model before we smoothed it meaning that we had no choice but to start the whole process again.

This was very annoying for the group but we realised that it was initially our own fault as we should have created new saves at the beginning of starting each section of the tutorial videos/rigging process. This is since a skill that I will try to keep in mind, especially when I am going to be redoing the platypus.


I managed to get it modeled again and UV mapped all in one day which then left me Sunday and Monday to get ready to the animating stage again. This was a big struggle and involved a lot of work but I managed to be able to model everything pretty quickly as I had previously done it anyway, but UV mapping was a little bit more difficult. It was a long process but I managed to get this stage done without any problems, ensuring that I deleted the history at every stage in order to not have any of the problems from last time when it came to rigging.


I then moved onto rigging the platypus, again as I had already done this stage with the raccoon model, as I was not there to do the platypus', and I had done my aliens as well, so I was fairly confident that I could get this stage done quickly and without ease, which I was able to, but I still did use the video guides that we were provided with, just to be sure that I didn't make any mistakes like what we had with the other model and rig.

I actually got the rig set up very quickly, even when watching the video guides I found that I was moving ahead and remembering details that needed adding in even before they are mentioned in the tutorial. I think that because I have had to remake this model so many times is actually a good thing as it has made me more confident with using Maya and I now feel confident about just getting on with rigging a model as I know how it should look and how the joints are going to end up working and how they parent to each other.




I then moved onto adding in the control points. Again I had to watch the tutorial videos in the background, but once again, like with the rigging, I was able to get this process done very quickly, especially the first stage of it when I added in the circular control points as they became second nature and I knew where they all needed adding.


I then colour coded them and ensured that each part was colour coded precisely to avoid any errors.

 
I then started to constrain my control points to the skeleton to ensure that they were connected properly. Again I used the same tools as before to do this using mainly the orient constraint but then also the parent and point constraint as well. This was exactly the same as before and once again I was able to redo this stage very quickly using all of the appropriate tools and also using our tutor Mat's video for reference.








I was then ready to bind the skeleton to the geometry, which is something that I nervous about due to the amount of issues that we had last time, but I am first creating a new save so that if something does go wrong during this stage I can start it again without having to worry about the model at all, I just have to paint the weights again.



So, once the model was bound I quickly checked that it was moving okay, which it was. But I first wanted to do a quick test in Unity to check for any problems with moving the skeleton so that if there was I would know that it is the binding that isn't working.

I was very happy with the result, there were a few issues with the look of some of the geometry being influenced where it shouldn't, but this is only due to the fact that I haven't started weight painting yet. So at this current time I then started to do this, first ensuring to once again create another save file.


I then continued with the weight painting until I was happy with the final result. Stuart then textured the model again with the UV Map that I gave him and we were ready to start animating. This part of the project was very distressing as we had to complete over 3 weeks of work again in a very short space of time, but we managed to get it done and I am very happy with the final result.

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