Different object shadows behavior

[misha.physics]

I thought to post it in the D3D9 Client thread, but decided to create a new thread about shadows.
I'm not sure, maybe this was always, but I'm noticing the object shadows problems both in Orbiter 2016 and OpenOrbiter. The shadows aren't exactly on the ground. They can be either above or below the surface. It appears even if the surface elevation is disabled, but the problem is less noticeable. There's the difference between shadows from the pre-defined objects (like BLOCK) and shadows from objects with a custom mesh. I see that the shadows behavior depends on:
1) Default objects or custom meshes.
2) Surface elevation on/off.
3) "Vessel mapping" in advanced D3D9 settings on/off.

Screenshots from OpenOrbiter 240315 (surface elevation is linear, vessel mapping is for all visible objects).

Shadow is above the ground:



Shadow is below the ground:



I think this requires further researches for OpenOrbiter development.

 

[LadyCroussette]

Yeah, sometimes it does that It seems to happen when the terrain is not completely flat, though it appear to be in your screenshots. I'm not quite sure of the "Why" myself.

 

[misha.physics]

The only ideal shadow I see is from an object with a custom mesh when the surface elevation is disabled:

 

[misha.physics]

The shadows are not drawn on the Delta Glider, or any surface but the ground... weird! is there a special computation of the received shadows for the "ground" and not for any other object? (hence, the shadow of the vessel when we approach a pad on any planet or moon)

We can have shadows on objects like this, although the first image look strange (entire shadow on the ground):



It corresponds to the Self Shadows section in advanced D3D9 settings.

 

[Buck Rogers]

This is the biggest shadow killjoy IMO. In shadow but fully lit! (O2016, don't know if it's different in O24)

 

[LadyCroussette]

This is the biggest shadow killjoy IMO. In shadow but fully lit! (O2016, don't know if it's different in O24)
View attachment 39057

I mean... to be fair...

 

[Buck Rogers]

reflected lighting from the ground, and different time of "day", notice how white the ground is (and does the camera have lighting?).
But a salesman would say Orbiter just perfectly replicates NASA archive photos!

 

[Boxx]

We can have shadows on objects like this, although the first image look strange (entire shadow on the ground):

The problem is about the shadows (whatever the shadowing object) onto custom objects (onto pre-defined objects like BLOCK seems ok, as one can see from your tests).
As illustrated by @Buck Rogers above, actually.