[Bf-committers] BGE Proposal: "Character" physics object type

Denis Washington denisw at online.de
Tue Aug 23 10:33:08 CEST 2011


This is the first time I am trying to get in touch with the Blender 
developer community, so please forgive me if this is the wrong 
communication channel for the following proposal. Also, let me tell you 
that I really love Blender, and would like to thank everyone who has 
contributed to it and made it what it is! You're my heroes. :)

I recently investigated the Blender Game Engine for a hobby game project 
- a 2.5D platformer - and as a first exercise,  I tried to get basic 
player character movement going. I expected this to be fairly easy to 
do, but I found out that it is actually pretty difficult to get right.

The reason is that none of the currently available physics object types 
in the game engine are really appropriate for this task. "Dynamic" is 
the closest match, but leads to several weird problems due to doing more 
sophisticated physics simulation than is actually needed - you see 
effects such as the player character sliding a bit after releasing a 
movement key, or bouncing when hitting the ground after jump or walking 
into walls. Playing around with physics and material settings (mass, 
friction etc.) reduce these issues, but don't completely remove them; it 
all still feels unsatisfactory and not very professional.

The point is that for this use case, there are actually no "real" 
physics needed at all; applying gravity and doing collision detection 
would actually be enough, and much more desirable as it provides the 
precision that the sophisticated physics types lack. In addition, such 
an implementation would be much more efficient.

Unfortunately, such a solution would currently have to be implemented 
manually by writing a Python script which applies gravity and handles 
collisions manually. This is a shame, because I believe that the need 
for such behavior is very, very common - almost every first-person 
shooter and platform game uses such reduced physics for player 
characters and enemies, for instance - and should not have to be 
implemented by every game developer needing it individually. Also, the 
current situation is frustrating for newcomers: about the first thing 
almost any beginner will try to do is to make some kind of object move 
like in an FPS / jump'n'run game, and being confronted with weird 
bouncing and sliding behavior in these first steps is not exactly 

Therefore, I propose the addition of a new physics object type named 
"Character" which applies the described basic means of physics to the 
object. This would provide BGE users with a simple way to get player 
character movement working as expected. Its implementation could use 
Bullet's "kinematic character controller" [1], which is exactly meant 
for this use case and has useful parameters such as step height (so that 
the character can walk over small steps, such as stairs, automatically).

What do you think?



More information about the Bf-committers mailing list