Stumbling Toward 'Awesomeness'

A Technical Art Blog

Wednesday, March 4, 2009

Common Character Issues: Attachments

I love this picture. It illustrates a few large problems with video games. One of which I have wanted to talk about for a while: Attachments of course. I am talking about the sword (yes, there is a sword, follow her arm to the left side of the image..)

Attaching props to a character that has to dynamically be seen from every angle through thousands of animations can be difficult. So difficult that people often give up. This was a promotional image for an upcoming Soul Calibur title, this goes to show you how difficult the issue is. Or maybe no one even noticed she was holding a sword. So let’s look at a promotional image from another game:

Why does it happen?

Well, props are often interchangeable. Many different props are supposed to attach to the same location throughout the game. This is generally done by marking up the prop and the skeleton with two attachment points that snap to one another.

In this case you often have one guy modeling the prop, one guy placing the skeleton, and one guy creating the animation. All these people have to work together.

How can we avoid these problems?

This problem is most noticeable at the end of the line: you would really only see it in the game. But this is one of the few times you will hear me say that checking it ‘in the engine’ is a bad idea. It’s hard enough to get animators to check their animation, much less test all the props in a ‘prop test level’ of sorts.

I feel problems like this mainly show up in magazines and final games because you are leaving it up to QA and other people who don’t know what to look for. There was a saying I developed while at Crytek when trying to impart some things on new tech art hires: “Does QA know what your alien should deform like? And should they?” The answer is no, and it also goes for the things above. Who knows how robotnik grips his bow.. you do, the guy rigging the character.

So in this case I am all for systems that allow animators to instantly load any common weapons and props from the game directly onto the character in the DCC app. You need a system that allows animators to be able to attach any commonly used prop at any time during any animation (especially movement anims)

Order of operations

Generally I would say:

  1. The animator picks a pivot point on the character. They will be animating/pivoting around this.
  2. The tech artist ‘marks’ up the skeleton with the appropriate offset transform.
  3. The modeler ‘marks’ his prop and tests it (iteratively) on one character
  4. The tech artist adds the marked up prop (or low res version) to a special file that is streamlined for automagically merging in items. Then adds a UI element that allows the animator to select the prop from a drop down and see it imported and attached to the character.


I can remember many heated discussions about problems like this. The more people that really care about hte final product, and the more detailed or realistic games and characters get, the more things like this will be scrutinized.

This is more of a simple problem that just takes care and diligence, whereas things like multiple hand positions and hand poses are a little more difficult. Or attachments that attach via a physics constraint in the engine. There are also other, much more difficult issues in this realm, like exact positioning of AI characters for interacting with each other and the environment, which is another tough ‘snap me into the right place’ problem dealing with marking up a character and an item in the world to interact with.

posted by Chris at 11:25 AM  


  1. Couldn’t agree more. It’s amazing how many problems can be made trivial to fix by just increasing the visibility of the data at a much earlier stage. Too often DCC+Engine construes one big black box where a whole team throws in data on one side and out comes a complex, intricate scene at the other end. No breaking it down, no isolating pieces, no quick turnaround to find and fix visual problems.

    Comment by peirz — 2009/03/04 @ 2:24 PM

  2. That’s all true, and things like these will often get lower priority when you’re rushing to just complete the schedule of animations on your plate, but you’re right in saying that there’s no excuse and things like this will come under more scrutiny in the future.

    In the first picture though, I’m pretty sure you were the only one looking at the sword. But seriously, I’ve found that if there’s a bad screenshot to be found, the marketing guys will use it.

    Comment by the alsoran — 2009/03/04 @ 3:17 PM

  3. Yea, I totally feel you on this one. The last game I worked on at my studio we were constantly battling with weapons and prop lining up with the animations. So there was a lot of back and for modifying the animations if a prop was updated. Once I came onto my current project that is wrapping up I made it a point to develop a 3dsmax tool that references our props and attaches them in the same manner that the game does. So when an animator goes to create an animation set the drop the weapon manager tool and select the prop they want to animate with. They don’t have to be technical because the tool merges in the prop and positions it appropriately. Anytime the weapon is updated, the attach points should remain the same, all they have to do is hit the update button on the tool and they will have the latest version of the weapon. This worked out great and the animators didn’t have to worry about how the weapons were being attached or redo any previous work.

    Comment by @MeatPlowz — 2009/03/04 @ 6:08 PM

  4. Im struggling with some prop animation at the moment. At least, I now know that i’m not alone.

    Comment by klingos — 2009/06/30 @ 5:54 PM

RSS feed for comments on this post. TrackBack URI

Leave a comment

Powered by WordPress