# Board index » delphi » Help with graphics/geometry problem.

## Help with graphics/geometry problem.

I've been trying for a week to figure out how to make an object sit anywhere
on a plane... when the plane can be tilted in any direction.

The plane is a triangle; and as far as I remember a plane only needs two
vectors to define it.

I have access to the normal vector of the plane, but being a 3d idiot I
don't really understand how to use it.  I also know the ax+by+cz formula but
don't know how to plug in the plane numbers.

Here's the application:  a terrain map made up of triangles rises and falls
to create undulations.  The object (camera) should be able to move over any
triangle... and its y coordinate should adjust to the slope of the triangle.

I'm using Delphi 5 and GLScene.

## Re:Help with graphics/geometry problem.

I figured this out.

For one arm and one leg I will give you the answer if you email me :)

##### Quote
"RHayes" <r...@cadvision.com> wrote in message news:3a0cf494\$1_1@dnews...
> I've been trying for a week to figure out how to make an object sit
anywhere
> on a plane... when the plane can be tilted in any direction.

> The plane is a triangle; and as far as I remember a plane only needs two
> vectors to define it.

> I have access to the normal vector of the plane, but being a 3d idiot I
> don't really understand how to use it.  I also know the ax+by+cz formula
but
> don't know how to plug in the plane numbers.

> Here's the application:  a terrain map made up of triangles rises and
falls
> to create undulations.  The object (camera) should be able to move over
any
> triangle... and its y coordinate should adjust to the slope of the
triangle.

> I'm using Delphi 5 and GLScene.