I am trying to render a 3d model of a bmx bike.

The problem is, when I use the lib3ds mesh matrices, the bike renders completely wrong with bike components drawing all over the place.

It almost works when I don't use the mesh matrices from the lib3ds file, but some bike components are displayed incorrectly, so I probably need to use them.
I have checked the values of the mesh matrices and they are not identity matrices.

I use the following code to store the modified matrix for a mesh of the bike:

float meshMat[4][4];
lib3ds_matrix_copy(meshMat, mesh->matrix);
lib3ds_matrix_inv(meshMat);

pMesh->m_matTransformationMatrix = glm::mat4(
    meshMat[0][0], meshMat[0][2], meshMat[0][1], meshMat[0][3],
    meshMat[1][0], meshMat[1][2], meshMat[1][1], meshMat[1][3],
    meshMat[2][0], meshMat[2][2], meshMat[2][1], meshMat[2][3],
    meshMat[3][0], meshMat[3][2], meshMat[3][1], meshMat[3][3]
);

I use the following code when rendering a mesh of the bike:

glUniformMatrix4fv(glGetUniformLocation(getGameEngine()->m_uiProgram1, "model"), 1, GL_FALSE, glm::value_ptr(pMesh->m_matTransformationMatrix));

I use this glsl code for my vertex shader:

#version 330

in vec3 in_position;
uniform mat4 camera;
uniform mat4 model;

void main(void)
{
    gl_Position = camera * model * vec4(in_position,1);
}

I'm currently not using my matrix (pos, rot & scale) for the bike, to less complicate things, so I'm only using the matrix from lib3ds currently.

I have switched y and z for all 4 vectors in the lib3ds matrix, because I have Y and Z switched in OpenGL. 

I see that many examples on the net use glMultMatrix but that is an outdated OpenGL function, I am using the model in the GPU shaders.

Can anyone help?

If you need to see more code, just ask and I'll provide it.

Thanks,
Mex

First thing is to render it well from 'cpu' side. That means, do all your maths calculations on the cpu side (use lib3ds_matrix_identity, lib3ds_matrix_translate_xy and lib3ds_matrix_mult in order to calculate the static positions of the vertices).

Once all of this works, this will just be a matter of sending these matrices information to the GPU.

One other thing to keep in mind is if you load by nodes (and you should, except if for some reasons the file has no nodes informations) the child node will inherit the coordinate system of its parent.