Why does a 'collision' cube make my scenery object invisible.

[jgarnold]

I have a scenery object of a large pier which without a cube marked MSFS Invisible shows it displays in MSFS when I load the project.

When I enclose the object with a mesh cube with material set to MSFS Invisible and Collision 'ticked' load I load the project the pier does not display.

I have used 'collision' cubes around objects before and never had them not display.

Any ideas what I could try?

 

[Nervegas]

I would use the collider gizmos that come with the Asobo blender plugin. Shift + A or go to Add while in Object Mode context and nearish the bottom should be a tab labeled Flight Simulator Collision, you can make a sphere, cube or cylinder shaped collider. This will get exported in the GLTF with the correct attributes for the sim to recognize. They are also optimized in the sim over mesh colliders. Edit: I just realized this may be the source of your previous collider issues if you havent been using the gizmos. The SDK mentions that mesh colliders can be, weird.

 

[jgarnold]

Thanks. I was not aware of the collider. Also I had a thought that perhaps the 3d cursor and/or origin point for the object had been mucked up when I added the mesh cubes (2) which made the object NOT appear where it was (I was updating the entire model which had already been placed) and haven't had a chance to check that theory out yet.
I certainly will though check out the collider. Thanks again

 

[jgarnold]

I added the collider (shift A and select cube) and positioned it around my scenery object. It doesn't work. I can drive my aircraft straight through it. Is there something else I need to do?

 

[superspud]

Is the collision box inside the object's collection in Blender?

If it isn't then it won't work.

I always click on the mesh first and then add the collision box to make sure it's attached.

 

[jgarnold]

I am sure it is ?

 

[Nervegas]

I am sure it is ?

View attachment 86863

Those are in the collection, but are not parented to a mesh, like spud said if you select the mesh you want it to be attached to before adding it, it should parent it to that mesh, otherwise you can just move it in the layer grouping to be parented to one of them.

 

[jgarnold]

Should I then Join all the meshes which make up the pier or will the collision box detect an aircraft 'touching' any part of the collision box (or only the mesh which has the collision box attached). The reason I ask is that using the MSFS collision box I (for another object which worked ok) if the floats on a floatplane 'contacted' the dock the floatplane would 'mount' the dock instead of just bumping off it even though the 'box' was 2 meters higher than the actual dock. I hope I have explained that enough.
I have never used this collision box before and don't even know if it should be scaled to enclose the mesh or is MSFS smart enough to know that the mesh it is attached to is all subject to collision or is the collision detection only for the position and size of the 'box'?

 

[Nervegas]

Should I then Join all the meshes which make up the pier or will the collision box detect an aircraft 'touching' any part of the collision box (or only the mesh which has the collision box attached). The reason I ask is that using the MSFS collision box I (for another object which worked ok) if the floats on a floatplane 'contacted' the dock the floatplane would 'mount' the dock instead of just bumping off it even though the 'box' was 2 meters higher than the actual dock. I hope I have explained that enough.
I have never used this collision box before and don't even know if it should be scaled to enclose the mesh or is MSFS smart enough to know that the mesh it is attached to is all subject to collision or is the collision detection only for the position and size of the 'box'?

It's using the box itself as the collider, so give it just a bit of padding to fully enclose the visible meshes. It's ignoring the mesh geometry to calculate the collision. And you don't need to join the meshes, you can just use as many gizmos as you need to get the collider shape you want.

 

[jgarnold]

That worked fine EXCEPT although one of my collision boxes 'encloses' a floating dock the boardwalk being just 0.6 meters above water, when a floatplane collides with it going forwards even at a slow speed (engine idling only) the floatplane 'climbs' the floating dock end ends up with the floats sitting on the floating dock. As the top of the collision box is well above the height of the floating dock I would have though that 1) the floatplane would not 'climb' the collision box 2) the floatplane would end up on top of the collision box.
Is there method to add a mesh cube on the floating dock mesh and have it NOT display and attach a collision box to that mesh?

[added later] obviously MSFS uses the height of the object not the height of the collision box as I added a collision box to end of a pier which is 2-3 meters high and an aircraft collision does NOT result if the floatplane 'climbing' the object it simply bumps off it.

 

[Nervegas]

That worked fine EXCEPT although one of my collision boxes 'encloses' a floating dock the boardwalk being just 0.6 meters above water, when a floatplane collides with it going forwards even at a slow speed (engine idling only) the floatplane 'climbs' the floating dock end ends up with the floats sitting on the floating dock. As the top of the collision box is well above the height of the floating dock I would have though that 1) the floatplane would not 'climb' the collision box 2) the floatplane would end up on top of the collision box.
Is there method to add a mesh cube on the floating dock mesh and have it NOT display and attach a collision box to that mesh?

[added later] obviously MSFS uses the height of the object not the height of the collision box as I added a collision box to end of a pier which is 2-3 meters high and an aircraft collision does NOT result if the floatplane 'climbing' the object it simply bumps off it.

Excellent to know, seems like it should work with some fiddling.

 

[=rk=]

FYI, "crash boxes" were added to an earlier version of the sim to increase realism by creating consequences for collisions with objects, on the logic that crash damage was not allowed in FSX, but crash consequences were. If an airplane contacts a dock hard enough to "bounce off it," there will be damage to both plane and dock and the crash box suggests this by bouncing the plane jarringly. Collision boxes were included to keep AI planes and vehicles from running into each other and the user plane.

It seems most likely that Asobo inherited these. For this application, the most appropriate legacy material type, imo would be "hard surface," or landable deck, which makes ships into aircraft carriers and is not supported by Asobo, with no intention of changing that status.

Excellent to know, seems like it should work with some fiddling.

It seems unlikely that one will be able to fiddle down a collision box to act as a hard surface against which one could, say, lash a floatplane, if that is the intended goal.

I am imagining this giant dome of transparent polygons, surrounding the float plane. Obviously, the user would have to "raise the lid," or "disable the force field" when approaching a collision box equipped dock, but - and this is dependent upon John setting collision box height exactly right - once within range, the user lowers the lid, or "initiates lashing operation" and the dome of invisible polygons gently bumps the plane back to center, right alongside the dock, every time it contacts the collision box.

 

[Nervegas]

FYI, "crash boxes" were added to an earlier version of the sim to increase realism by creating consequences for collisions with objects, on the logic that crash damage was not allowed in FSX, but crash consequences were. If an airplane contacts a dock hard enough to "bounce off it," there will be damage to both plane and dock and the crash box suggests this by bouncing the plane jarringly. Collision boxes were included to keep AI planes and vehicles from running into each other and the user plane.

It seems most likely that Asobo inherited these. For this application, the most appropriate legacy material type, imo would be "hard surface," or landable deck, which makes ships into aircraft carriers and is not supported by Asobo, with no intention of changing that status.

It seems unlikely that one will be able to fiddle down a collision box to act as a hard surface against which one could, say, lash a floatplane, if that is the intended goal.

I am imagining this giant dome of transparent polygons, surrounding the float plane. Obviously, the user would have to "raise the lid," or "disable the force field" when approaching a collision box equipped dock, but - and this is dependent upon John setting collision box height exactly right - once within range, the user lowers the lid, or "initiates lashing operation" and the dome of invisible polygons gently bumps the plane back to center, right alongside the dock, every time it contacts the collision box.

The SDK says to prefer the use of the collider gizmos over other solutions in big bold letters on the collision handling page. They may have inherited them, but the SDK guidance is current, and theyve certainly made updates to how collisions are handled several times. If the goal is to make parkable spaces, then multiple smaller collision boxes should work, they would just need some fine tuning. The idea being to fit a collision bound around the mesh utilizing primitive colliders, sort of an imposter for mesh collision with higher performance. The reason the "road material" collider is used for aircraft carriers etc is that it disables crash damage calc internally and makes a "driveable" hard surface. You could in theory use that to make a more precise hard surface around a more complex mesh.

 

[=rk=]

If the goal is to make parkable spaces, then multiple smaller collision boxes should work, they would just need some fine tuning.

The goal had been to raise the notion of the reality that any collision, by any aircraft whatsoever, beyond an extremely low, as in what should be easily controlled by any pilot already, speed, will result in damage, making any sort of collider that "bounces" to be fictional. I mean, if you want to figure out how to make your collider work exactly under, say, 4 knots and above that speed maybe reset the flight, or simply ignore the plane, that seems like it would be much more practical.

 

[jgarnold]

Thanks Rick and Nervegas.

I agree with your thoughts re collision and damage. However (maybe I missed this in your responses) when my floatplane 'touches' a tall structure with the collision box at much less than taxi speed (the speed from just having the engine at idle which is very slow) it bounces away as expected (never tried deliberately running into the structure at speed and why would I) but when it 'touches' a low structure at the same slow speed it doesn't bounce away it mounts the structure and I really was hoping that it would use the height of the collision box to determine if it could mount the structure or not.

Surely it should be controllable by the developer - if they want the aircraft to bounce away then they set the height of the collision box high and if they way the aircraft to mount the structure then they set the height of the collision box low.

I tried adding an MSFS invisible mesh cube over the dock and then tried to attach a collision box to the invisible mesh cube and it wouldn't work - displayed a cross instead of a (scalable) box.

 

[jgarnold]

Not sure if I have worked out a solution (to collision box over a low structure such as a floating dock).
As a box is not displayed when attaching to a mesh which has a MSFS Invisible material (it displays a cross instead which is impossible to scale to get it to cover the mesh cube) what I did is as follows

Add a mesh cube and resize and move it over the mesh you want to have collision. Do NOT give it a material
Add the collider box (it will display correctly) and scale and move it as required
Select the mesh cube and give it an MSFS INVISIBLE material
The collider box remains and doing a test gave better results.

I don't have time to test further as I am off on vacation.

 

[jgarnold]

Returned from vacation and trying to 'pick up the pieces' from where I left off and my mind must be back on vacation as I have forgotten what to do regarding attaching a collision box to a mesh.

I select the mesh to add 'collision' to and then select Add>Mesh>Cube which obviously is not the correct method.

Could someone put me right regarding adding collision material to a mesh as this ageing brain of mine is still on vacation.

 

[mamu]

Returned from vacation and trying to 'pick up the pieces' from where I left off and my mind must be back on vacation as I have forgotten what to do regarding attaching a collision box to a mesh.

I select the mesh to add 'collision' to and then select Add>Mesh>Cube which obviously is not the correct method.

Could someone put me right regarding adding collision material to a mesh as this ageing brain of mine is still on vacation.

Welcome back John!

To add a collision box, it is Add/FlightSimulatorCollision/Box Collision


If you instead want a collision material,
You need to Select the material, scroll down until you see the "Collision" checkbox property

 

[jgarnold]

Add/FlightSimulatorCollision/Box Collision

That's it. Completely forgot that.
Could you now please explain the difference between a collision material and a box collision or maybe better yo explain when the user would use one instead of the other? Do they both create the same result?

 

[mamu]

That's it. Completely forgot that.
Could you now please explain the difference between a collision material and a box collision or maybe better yo explain when the user would use one instead of the other? Do they both create the same result?

In my experience, the collision shape is 100% reliable, and is advised by Asobo themselves

The collision material can be used for oddly shaped objects, and works..mm..bad (is not always detected) so I don't recommended it, at least for scenery
The Collision material has a role in aircraft creation, maybe the cockpit