Materials and textures for most loaded OBJ files are not rendered...
Marcel Offermans
Radu Serban
Marcel,
Indeed, this is a known current limitation (bug if you wish) in the Irrlicht run-time visualization module.
I have recently redesigned the entire framework for specifying visualization models and rendering. The code is set up to make use of both the OBJ and any MTL file, but there’s still something I must be missing when creating the Irrlicht materials and mesh buffers
that prevents rendering of material textures.
I can think of 3 options for now:
- I will look again at this issue when I get a chance. However, it’s not a top priority right now (also because the expectation is that we will eventually replace Irrlicht run-time
visualization with a VSG-based system). So, you may have to wait a bit longer.
- You (or someone else familiar with Irrlicht) could help with a fix for this through a pull request
😊
For whoever is interested, the two relevant parts in the code to look at are: - Lines 717-739 in ChVisualSystemIrrlicht.cpp (where the Irrlicht mesh buffers are created)
- Function ChIrrNodeShape::UpdateTriangleMesh_mat of
ChIrrNodeShape.cpp (where the Irrlicht materials and buffers are populated)
- Instead of using a trimesh asset read from file (in which case Chrono constructs an internal mesh representation and also reads in visual materials which are later passed on the run-time
visualization system to be converted in their own objects), use a ChObjFileShape and attach that as a visual shape to your model. The difference is that a ChObjFileShape is only a reference to a Wavefront OBJ file which is passed as such to the visualization
system; if it knows how to do that, it is the renderer responsibility (in this case Irrlicht) to open that OBJ file (and any associated MTL files) and create its own internal meshes and materials. Irrlicht knows how to do that, and the material textures
show up fine if going this route.
For an example of this, look at the “Gator” vehicle model and something like demo_VEH_Gator.
--Radu
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Marcel Offermans
What is a "VSG-based system" out of interest?
Radu Serban
Marcel, assuming you are talking about option #2 I listed below, keep in mind that this is not a trivial task unless you have some experience with rendering pipelines in general and Irrlicht in particular. Also, this will not teach you
much about Chrono.
However, if you are interested in learning more about that kind of things, by all means, give it a shot.
VSG is VulkanSceneGraph. See https://vsg-dev.github.io/VulkanSceneGraph/
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Marcel Offermans
if (vis == VisualizationType::MESH && (m_has_obj || m_has_mesh)) {
auto obj_shape = chrono_types::make_shared<ChObjFileShape>();
obj_shape->SetFilename(vehicle::GetDataFile(m_vis_mesh_file));
body->AddVisualShape(obj_shape, ChFrame<>());
return;
}
# Material Count: 1
newmtl lambert15SG
Ns 0.000000
Ka 1.000000 1.000000 1.000000
Kd 0.500000 0.500000 0.500000
Ks 0.000000 0.000000 0.000000
Ke 0.000000 0.000000 0.000000
Ni 1.000000
d 1.000000
illum 1
map_Kd textures/Bus_Texturing_Bus_Chassis_BaseColor.jpg
map_Pr textures/Bus_Texturing_Bus_Chassis_Roughness.jpg
map_Pm textures/Bus_Texturing_Bus_Chassis_Metallic.jpg
map_d textures/Bus_Chassis_Opacity.jpg
Radu Serban
Chrono::VSG is being developed in the feature/vsg branch. Right now, it’s pretty much a one-man job, with Rainer - our collaborator in Germany – doing all the heavy lifting. If you are interested and willing to help, that would be great!
Best,
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Marcel Offermans
Radu Serban
Indeed, getting all dependencies right takes a bit of work. But yes, if you get all of them straightened out, Chrono::VSG should build fine.
VSG is itself under continuous development and the hope is that they will streamline the installation process at some point. There’s not much point for us to try to do anything about it until then.
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Marcel Offermans
Greetings, Marcel