Bug: Assimp doesn't load all geometries for some meshes

[AndreyKlimenk0]

I have a problem with loading some fbx models. I use assimp for loading models and my first a test model loads correctly but I tried to load others models and get models with not whole geometry. I try to solve the proble but stuck and have no idea why this happens. `bool Mesh_Loader::load(const char *file_name, bool print_info) { print("Mesh_Loader::load: Started to load {}.", file_name);

String path;
build_full_path_to_model_file(file_name, path);

if (!file_exists(path)) {
	print("Mesh_Loader::load: Failed to load. {} does not exist in model folder.", file_name);
	return false;
}
auto postProcessSteps = (aiPostProcessSteps)(
	aiProcess_Triangulate |
	aiProcess_SortByPType |
	aiProcess_CalcTangentSpace |
	aiProcess_FlipUVs |
	aiProcess_JoinIdenticalVertices |
	aiProcess_ConvertToLeftHanded);

scene = (aiScene *)importer.ReadFile(path, postProcessSteps);
if (!scene) {
	print("Mesh_Loader::load: Failed to load a scene from {}.", file_name);
	return false;
}
if (print_info) {
	print_nodes(scene, scene->mRootNode);
}

auto matrix = aiMatrix4x4(
	1.0f, 0.0f, 0.0f, 0.0f,
	0.0f, 1.0f, 0.0f, 0.0f,
	0.0f, 0.0f, 1.0f, 0.0f,
	0.0f, 0.0f, 0.0f, 1.0f);

process_nodes(scene->mRootNode, matrix);
print("Mesh_Loader::load: {} was load successfully.", file_name);
return true;

}

void Mesh_Loader::process_nodes(aiNode *node, aiMatrix4x4 parent_transform_matrix) { Array<String> processed_meshes; for (u32 i = 0; i < node->mNumMeshes; i++) { u32 mesh_index = node->mMeshes[i]; const char *mesh_name = scene->mMeshes[mesh_index]->mName.C_Str();

	Mesh_Instance *mesh_instance = NULL;
	if (!mesh_instance_table.get(mesh_name, &mesh_instance)) {
		mesh_instance = new Mesh_Instance();
		mesh_instance->name = mesh_name;
		process_mesh(scene->mMeshes[mesh_index], &mesh_instance->mesh);

		mesh_instance_table.set(mesh_name, mesh_instance);
		mesh_instances.push(mesh_instance);
	}
	aiMatrix4x4 temp = parent_transform_matrix * node->mTransformation;
	Matrix4 transform_matrix = {
		temp.a1, temp.a2, temp.a3, temp.a4,
		temp.b1, temp.b2, temp.b3, temp.b4,
		temp.c1, temp.c2, temp.c3, temp.c4,
		temp.d1, temp.d2, temp.d3, temp.d4,
	};
	transform_matrix = transpose(&transform_matrix);

	mesh_instance->transform_matrices.push(transform_matrix);
}

aiMatrix4x4 transform_matrix = node->mTransformation * parent_transform_matrix;

for (u32 i = 0; i < node->mNumChildren; i++) {
	process_nodes(node->mChildren[i], transform_matrix);
}

}

void Mesh_Loader::process_mesh(aiMesh *ai_mesh, Triangle_Mesh *mesh) { mesh->vertices.clear(); mesh->indices.clear();

for (u32 i = 0; i < ai_mesh->mNumVertices; i++) {
	Vertex_XNUV vertex;

	vertex.position.x = ai_mesh->mVertices[i].x;
	vertex.position.y = ai_mesh->mVertices[i].y;
	vertex.position.z = ai_mesh->mVertices[i].z;

	if (ai_mesh->HasTextureCoords(0)) {
		vertex.uv.x = (float)ai_mesh->mTextureCoords[0][i].x;
		vertex.uv.y = (float)ai_mesh->mTextureCoords[0][i].y;
	}

	if (ai_mesh->HasNormals()) {
		vertex.normal.x = ai_mesh->mNormals[i].x;
		vertex.normal.y = ai_mesh->mNormals[i].y;
		vertex.normal.z = ai_mesh->mNormals[i].z;
	}

	mesh->vertices.push(vertex);
}

for (u32 i = 0; i < ai_mesh->mNumFaces; i++) {
	aiFace face = ai_mesh->mFaces[i];

	assert(face.mNumIndices == 3);
	for (u32 j = 0; j < face.mNumIndices; j++) {
		mesh->indices.push(face.mIndices[j]);
	}
}

}` Assimp log: Info, T9096: Load d:\dev\hades-engine\data\models\Scene_Demo2.fbx

Assimp log: Debug, T9096: Assimp 5.2.2275576043 amd64 msvc debug shared singlethreadedsingle :

Assimp log: Info, T9096: Found a matching importer for this file format: Autodesk FBX Importer.

Assimp log: Info, T9096: Import root directory is 'd:\dev\hades-engine\data\models'

Assimp log: Debug, T9096: Reading FBX file

Assimp log: Debug, T9096: Tokenizing binary FBX file

Assimp log: Debug, T9096: FBX version: 7300

Assimp log: Debug, T9096: Parsing FBX tokens

Assimp log: Debug, T9096: Creating FBX Document

Assimp log: Debug, T9096: FBX Version: 7300

Assimp log: Info, T9096: FBX: ignoring empty AnimationStack (using IK?): Unreal Take

Assimp log: Warn, T9096: FBX-DOM (TOK_KEY, offset 0x38695) property table (Properties70) not found

Assimp log: Warn, T9096: FBX-DOM (TOK_KEY, offset 0x388cd) property table (Properties70) not found

Assimp log: Warn, T9096: FBX-DOM (TOK_KEY, offset 0x38b05) property table (Properties70) not found

Assimp log: Warn, T9096: FBX-DOM (TOK_KEY, offset 0x38d47) property table (Properties70) not found

Assimp log: Debug, T9096: UpdateImporterScale scale set: 0.01

Assimp log: Info, T9096: Entering post processing pipeline

Assimp log: Debug, T9096: MakeLeftHandedProcess begin

Assimp log: Debug, T9096: MakeLeftHandedProcess finished

Assimp log: Debug, T9096: FlipUVsProcess begin

Assimp log: Debug, T9096: FlipUVsProcess finished

Assimp log: Debug, T9096: FlipWindingOrderProcess begin

Assimp log: Debug, T9096: FlipWindingOrderProcess finished

Assimp log: Info, T9096: Leaving post processing pipeline

[tellypresence]

Can you attach to this ticket model file(s) that fail to load?

[AndreyKlimenk0]

@tellypresence As I remember with this model I have the problem. Scene_Demo2.zip

[teub]

I couldn't update to the latest version of assimp because of an issue very similar to this one. I can't easily share my fbx or a repro yet, but I could spend more time on it if AndreyKlimenk0's report isn't enough, or if the resolution of this issue doesn't fix it.

[stephengold]

I'm experiencing a similar issue, where the first few imports go well but after a while imports of animated models return incomplete meshes. My issue isn't specific to FBX, nor does it point to models Assimp can't handle, since the same model imports fine if the application is restarted and the model that failed is imported first. I've never seen issue this affect a model without an armature/rig/skeleton.

My issue (which might not be the same as Andrey's) suggests to me some state internal to Assimp is not getting reset between invocations of aiImportFile(). I always invoke aiReleaseImport() after each import, so the bug might be there.

[kimkulling]

Good to know. I guess there is a bug in the new animated esh importer.

[teub]

Is there any chance the latest version fixes this ?

[teub]

(I checked, it's not - in case anyone is wondering)