3d model not rendered (DirectX 12) - direct3d

Question

I am developing a small program that load 3d models using assimp, but it does not render the model. At first I thought that vertices and indices were not loaded correctly but this is not the case ( I printed on a txt file vertices and indices). I think that the probem might be with the position of the model and camera. The application does not return any error, it runs properly.
Vertex Struct:
struct Vertex {
XMFLOAT3 position;
XMFLOAT2 texture;
XMFLOAT3 normal;
};
Input layout:
D3D12_INPUT_ELEMENT_DESC inputLayout[] =
{
{ "POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
{ "TEXCOORD", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 12, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 },
{ "NORMAL", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, D3D12_APPEND_ALIGNED_ELEMENT, D3D12_INPUT_CLASSIFICATION_PER_VERTEX_DATA, 0 }
};
Vertices, texcoords, normals and indices loader:
model = new ModelMesh();
std::vector<XMFLOAT3> positions;
std::vector<XMFLOAT3> normals;
std::vector<XMFLOAT2> texCoords;
std::vector<unsigned int> indices;
model->LoadMesh("beast.x", positions, normals,
texCoords, indices);
// Create vertex buffer
if (positions.size() == 0)
{
MessageBox(0, L"Vertices vector is empty.",
L"Error", MB_OK);
}
Vertex* vList = new Vertex[positions.size()];
for (size_t i = 0; i < positions.size(); i++)
{
Vertex vert;
XMFLOAT3 pos = positions[i];
vert.position = XMFLOAT3(pos.x, pos.y, pos.z);
XMFLOAT3 norm = normals[i];
vert.normal = XMFLOAT3(norm.x, norm.y, norm.z);
XMFLOAT2 tex = texCoords[i];
vert.texture = XMFLOAT2(tex.x, tex.y);
vList[i] = vert;
}
int vBufferSize = sizeof(vList);
Build of the camera and views:
XMMATRIX tmpMat = XMMatrixPerspectiveFovLH(45.0f*(3.14f/180.0f), (float)Width / (float)Height, 0.1f, 1000.0f);
XMStoreFloat4x4(&cameraProjMat, tmpMat);
// set starting camera state
cameraPosition = XMFLOAT4(0.0f, 2.0f, -4.0f, 0.0f);
cameraTarget = XMFLOAT4(0.0f, 0.0f, 0.0f, 0.0f);
cameraUp = XMFLOAT4(0.0f, 1.0f, 0.0f, 0.0f);
// build view matrix
XMVECTOR cPos = XMLoadFloat4(&cameraPosition);
XMVECTOR cTarg = XMLoadFloat4(&cameraTarget);
XMVECTOR cUp = XMLoadFloat4(&cameraUp);
tmpMat = XMMatrixLookAtLH(cPos, cTarg, cUp);
XMStoreFloat4x4(&cameraViewMat, tmpMat);
cube1Position = XMFLOAT4(0.0f, 0.0f, 0.0f, 0.0f);
XMVECTOR posVec = XMLoadFloat4(&cube1Position);
tmpMat = XMMatrixTranslationFromVector(posVec);
XMStoreFloat4x4(&cube1RotMat, XMMatrixIdentity());
XMStoreFloat4x4(&cube1WorldMat, tmpMat);
Update function :
XMStoreFloat4x4(&cube1WorldMat, worldMat);
XMMATRIX viewMat = XMLoadFloat4x4(&cameraViewMat); // load view matrix
XMMATRIX projMat = XMLoadFloat4x4(&cameraProjMat); // load projection matrix
XMMATRIX wvpMat = XMLoadFloat4x4(&cube1WorldMat) * viewMat * projMat; // create wvp matrix
XMMATRIX transposed = XMMatrixTranspose(wvpMat); // must transpose wvp matrix for the gpu
XMStoreFloat4x4(&cbPerObject.wvpMat, transposed); // store transposed wvp matrix in constant buffer
memcpy(cbvGPUAddress[frameIndex], &cbPerObject, sizeof(cbPerObject));
VERTEX SHADER:
struct VS_INPUT
{
float4 pos : POSITION;
float2 tex: TEXCOORD;
float3 normal : NORMAL;
};
struct VS_OUTPUT
{
float4 pos: SV_POSITION;
float2 tex: TEXCOORD;
float3 normal: NORMAL;
};
cbuffer ConstantBuffer : register(b0)
{
float4x4 wvpMat;
};
VS_OUTPUT main(VS_INPUT input)
{
VS_OUTPUT output;
output.pos = mul(input.pos, wvpMat);
return output;
}
Hope it is a long code to read but I don't understand what is going wrong with this code. Hope somebody can help me.

Answer 1

A few things to try/check:
Make your background clear color grey. That way, if you are drawing black triangles you will see them.
Turn backface culling off in the rendering state, in case your triangles are back to front.
Turn depth test off in the rendering state.
Turn off alpha blending.
You don't show your pixel shader, but try writing a constant color to see if your lighting calculation is broken.
Use NVIDIA's nSight tool, or the Visual Studio Graphics debugger to see what your graphics pipeline is doing.
Those are usually the things I try first...