New Content??

[Tsar Hoikas]

But if triangle mesh is chosen for surfaces and the Normal is pointing to the wrong direction, then it is also impossible to see a texture, unless the twoside texturing option is chosen.
Personely i seldom choose twoside texturing and avoid it, only for tree leaves or simular situations where it is absolutely necessary.

NEVER use the same mesh for a triangle mesh collider and a visual. Triangle mesh (proxy) colliders should always be separate objects with as few faces as necessary.

[Deledrius]

Good point.

I should note that the colliders I've seen this problem with are not made directly from visible geometry. These are invisible-wall sorts of colliders which have no drawable analogue, or ones which are approximations such as on stairs and bridges.

[Trekluver]

Even if these issues are fixed when converting ages between Havok and PhysX, how will you know that it won't have to be done again once Bullet is successfully implemented? Does Bullet have similar issues as Havok? I hate to sound bleak about it, but as much as my new content loving self hates to say it, aside from this initial testing, I see no real reason to waste time on something that's just going to have to be done again in a year or two.

[Deledrius]

As I said, this is the result of Havok not caring about facing, which meant that some artists didn't pay any attention to it, as it didn't matter for PotS. If they did anyway, their Age will already convert correctly.

Like some problems in MOULa for which we need the Age source to fix now that we've made fixes to the engine, it's a question of bugs which were there in the geometry but were not a problem because other bugs (by design or not) were covering them.

IOW, fixing this now still fixes it for later.

[GPNMilano]

But if triangle mesh is chosen for surfaces and the Normal is pointing to the wrong direction, then it is also impossible to see a texture, unless the twoside texturing option is chosen.
Personely i seldom choose twoside texturing and avoid it, only for tree leaves or simular situations where it is absolutely necessary.

NEVER use the same mesh for a triangle mesh collider and a visual. Triangle mesh (proxy) colliders should always be separate objects with as few faces as necessary.

I'm sorry. I have to ask. Why is this exactly? Triangle-Mesh colliders are attached to surfaces all throughout Uru, in almost every Cyan age, and I've never had issues with them or using them. In fact the Max Plugin specifically has the option of the Terrain so surfaces can be physicals as well. The information for them are kept separate in the PRPs. So what's the issue here?

[Tsar Hoikas]

Triangle mesh colliders are slow, especially in Havok. Collision must be computed for all the faces in the triangle mesh. This can quickly become a huge choke point (especially in Havok). It's best to specify a separate collision mesh that is either simpler than the visual mesh or is built to be a convex hull. I'm pretty sure Cyan's plugin shouts about setting the collision to "explicit" just as much as I am here

Many of Cyan's collision meshes are simplified versions of the visual mesh.

[Deledrius]

Even for accessible areas of organic terrain? It seems to me that anything else would not work correctly.

[Trekluver]

IOW, fixing this now still fixes it for later.

Sounds good then; glad to know my worries are not a big deal.

[GPNMilano]

I've personally never noticed the plugin raising any complaints when the terrain is set to exact. Only when it's trying to make a convex hull does it sometime throw up an error for me. And one of my ages has 48 objects with physicals attached to surfaces. Mostly for the ground and large rocks.

[Sirius]

Cyan uses exact collision for:
- terrains such as the Relto island, on which you can walk and need an exact position of the avatar on the surface it's walking on.
- colliders that manages all collision for a whole part of an Age. This collider is really simple (it rarely uses the same faces as the visible object).
Cyan uses hull bounds mostly for regions and clickables, since you rarely need a lot of precision with it.
They sometimes use box collision for clickables as well.
In Myst V, they use a LOT of box bounds, maybe because ODE manages it better. That's why the collisions often seem less accurate.

In fan ages however, modellers rarely care about simplifying the collision. It often ends up with EVERY single objects using Triangle Mesh, even for objects with a lot of vertices you often cannot touch since they are too far from the avatar, and this slows down a lot the engine.