How can I change the shading of a model?

I made a simple box-shaped model in Gmax, and am using it in one of my maps.

However, there is a shading on this model such that the texture gets progressively darker toward certain vertices of the model.

I'd like to make it so that there is no shading on the model. How can I do this?

Thanks!

Capt. Picard

Ah, Captain Picard, perhaps I can help you.
Convert you model into mdl. Open the mdl file with note pad. Go to the material block:

(just an example)
Material {
Layer {
FilterMode Transparent,
static TextureID 0,
TwoSided,
}
}

Add between the lines staic TextureID 0 (example!) and TwoSided the word Unshaded,.

Like this:

Material {
Layer {
FilterMode Transparent,
static TextureID 0,
TwoSided, <-
Unshaded,
}
}

That's it.
Then convert you file back to gmax file type.