I'm sending this email to my lecturer, but he might not get it at the weekend.
The hand in is on Friday and I need to get things moving by them.

Any help appreciated


I emailed you earlier today say that I may need help with trying to apply the
remote control car scenario to a similar scene of my own.
I?ve been working on it all day, but there are two problems which I?m having
difficulty understanding.

Essentially I have stripped the car demo down to its most basic parts. First I
left the wheels working as they would normally, then I tried removing them
altogether so I could have a proper understanding of how the car is driven.

I?ve placed links to my website for the five relevant files for this email at
the bottom, where I?ve explained each of them a little.
The first relevant file is located here at

When I applied these changes I was able to have the car moving along the
ground with a reasonable effect, so my next step was to import a scene of my
For simplification I have just used two rectangular objects in my scene; one
for the car ?chassis00? and one for the ground ?floor?. I have also kept in the
objects representing the four wheels, but for the time being I am not using

In order to have my floor placed directly beneath the car I have had to edit
its position on the Z-axis and increase it size. I?m not altogether sure why I
have had to do this because I would assume that in the 3D file used to create
this, the floor would have been placed in a similar position to mine
The code I?ve placed for this in the update hover is:

pMember.model("floor").transform.position = vector( 2.40471e3, 768.6797,
-181.3870 )
pMember.model("floor").transform.scale = vector( 30, 30, 1 )

I have two problems now though and this isn?t one of them

My first problem is not as apparent here in this current model as it was in
some earlier versions I?ve worked on, but it is still there. If you move my
object ?chassis00? around the plane for a short while, towards the edge but not
over it, it will eventually flip in the air.
The fact that flips so high is my second problem and I?ll go into that soon
but there is another effect going on here.
It appears to me that as my chassis is moved along the ground there is a
downward force being applied to it that is gradually pushing it into the ground
until it gets to the stage where it recognises the ground in front of it as
being a wall and it then flips away in response to having met a wall even
though there are no walls in this scene.
When I carry out the same test of moving the car along the ground using the
original cast member, I don?t get this response until I?ve hit my car into an
actual wall or object.

My second problem at the moment, I touched on in the first part, is the over
the top reaction whenever a ?chassis00? hits an object in either the original
cast member or my dummy version, where the car flips wildly into the air when I
hit something.
Unlike the first problem though I can see the general area of where I?ve made
my mistake.

In order to use an object that currently doesn?t have any wheels, I?ve deleted
a lot of the code in the ?raycast car? behaviour code. I have effectively taken
out any reference to the wheels themselves and replaced it where needed with
code I thought should apply the same response.
The most damaging aspect of this that I can see is that in the area ?repeat
with i = 1 to pWheelPointList.count? where they have repeated a process to
search for models under ray of each wheel and then apply the required point
velocity to the four corners of the car where the four wheels are. Here, rather
than repeat the process four times I have wanted to just apply a modelsunderray
to the chassis of the car to find the ?floor? and then apply the required force
to the centre of the car(pChassisRB.applyForce(force)
) rather than the four points (pChassisRB.applyForceAtPoint(force,

In order to compensate for the fact that there is now only one rather than
four forces at work, I have multiplied the equation that produces the force by
Firstly though, I?m not completely sure why I have to do this. I haven?t
figured out how the force that they are applying is only a quarter of what is
required (*4)
Secondly, this still doesn?t completely work. This approach means that the car
does hover above the ground, but whenever I hit something, things go badly
wrong and the car flips wildly in the air rather than it?s usual bounce.

I apologise for the length of this email (and if it?s not too coherent,
because I?m writing it fairly late at night), but as I mentioned I?ve spent
several days stuck on these problems and if you could take the time to help
point me in the right direction with them I could get our project moving again
I?m reasonably confident that after I understand what the problems are here
that the rest of the project will piece together quite smoothly.


The files related to this email are located at my newry portal website:

?Dummy Layout?
Relates to problem 1: When the car moves along the floor for a short while it
will eventually flip out as though it has hit a wall

?Dummy Version ? Max File?
Relates to problem 1: The 3DS Max file that includes the basic objects used in
the Dummy Layout?s 3D member.

?Original Scene ? Without Wheels(1)?
Relates to problem 1: In this version as long as the car is moved only on the
floor it hovers as normal
Also relates to problem 2: Whenever it hit?s a wall it flips wildly

?Original Scene ? With Wheels?
Relates to problem 2: A stripped down version of the remote control car demo.
Some non-vital parts of the ?raycast car? behaviour have been removed such as
the turning effects on the wheels.

?Original Scene ? Without Wheels(2)?
This is a working version of the demo with the wheels removed. It?s not a lot
different to the ?with wheels file?, but it shows that removing the wheels is
possible. My problem is though that I want to remove all of the code relating
to the wheels so I can focus on making the car work.