As a bit of a learning exercise for creating and rendering meshes and textures, I wanted to make a small add-on with a low-poly mesh that I could make from scratch, picking points off a drawing and making the mesh in a text editor. I picked a J-3 Cub as a suitable aircraft.
![Piper_L-4B_Grasshopper_3-view_line_drawing.png Piper_L-4B_Grasshopper_3-view_line_drawing.png](https://cdn.orbiter-forum.com/data/attachments/38/38418-b61a736067b9a84d6553cfbaffda1067.jpg)
So I pulled out a ruler and started triangulating the geometry and put it into a mesh file (attached). The geometry seems to be going well (I still have to do the fiddly round bits like the tires, struts, etc. but it's mostly there). Here's how it looks in Orbiter:
![Screenshot at 2024-05-28 22-20-49.png Screenshot at 2024-05-28 22-20-49.png](https://cdn.orbiter-forum.com/data/attachments/38/38420-89ed9a2fffc260bf8276d7946573b75a.jpg)
The geometry seems pretty solid so I must have the left-hand-rule under control. The wings and surfaces are essentially all 2D. To ensure they are opaque from all angles, I made two triangles for every three vertices, with the left hand convention setting opposite normals for both triangles.
But I am obviously having some rendering issues.
1. I can't seem to get reflections off any of the surfaces. I know this is set in the specular color setting of the surface materials in the mesh file, but no matter how I set them I seem to get just the same color with no illumination.
2. The transparent windscreens behave strangely. They seem to negate the transparency of whatever is behind them. If an opaque surface is behind it, that surface renders transparent, and vice versa. These surfaces are set just like the opaque surfaces, with two triangles with opposing normals, which I don't know if it is a part of the problem or the correct procedure.
Can anyone see what I might be doing wrong with respect to the rendering of these surfaces? If I can fix these things I think I can make a fun little add-on with a real propeller engine.
![Piper_L-4B_Grasshopper_3-view_line_drawing.png Piper_L-4B_Grasshopper_3-view_line_drawing.png](https://cdn.orbiter-forum.com/data/attachments/38/38418-b61a736067b9a84d6553cfbaffda1067.jpg)
So I pulled out a ruler and started triangulating the geometry and put it into a mesh file (attached). The geometry seems to be going well (I still have to do the fiddly round bits like the tires, struts, etc. but it's mostly there). Here's how it looks in Orbiter:
![Screenshot at 2024-05-28 22-20-49.png Screenshot at 2024-05-28 22-20-49.png](https://cdn.orbiter-forum.com/data/attachments/38/38420-89ed9a2fffc260bf8276d7946573b75a.jpg)
The geometry seems pretty solid so I must have the left-hand-rule under control. The wings and surfaces are essentially all 2D. To ensure they are opaque from all angles, I made two triangles for every three vertices, with the left hand convention setting opposite normals for both triangles.
But I am obviously having some rendering issues.
1. I can't seem to get reflections off any of the surfaces. I know this is set in the specular color setting of the surface materials in the mesh file, but no matter how I set them I seem to get just the same color with no illumination.
2. The transparent windscreens behave strangely. They seem to negate the transparency of whatever is behind them. If an opaque surface is behind it, that surface renders transparent, and vice versa. These surfaces are set just like the opaque surfaces, with two triangles with opposing normals, which I don't know if it is a part of the problem or the correct procedure.
Can anyone see what I might be doing wrong with respect to the rendering of these surfaces? If I can fix these things I think I can make a fun little add-on with a real propeller engine.