Prebroken destructible cylinder

Olli.

Im creating a cylinder which will be prebroken and destructible.

Now theres a problem that has risen to my mind. How can i keep the smooth normals of the cylinder?
If i break the surface in to seperate chunks, the normals will not make the object perfectly round.

There has to be a solution to this, since I've seen prebroken destructible smooth cylinders in other games for a long time, most recently in battlefield 3

commander_keen

I dont think there is any real way to get rid of weird shading in this situation without using object space normal maps or tangent space baking after the object is broken (and having proper tangent basis in bake and engine). Relying purely on vertex normals with "random" cuts in it is always going to give wavy deformed results, even if you try to preserve the original normals. If your object is primarily flat shaded then the results will probably be ok, A lot of destructible in bf3 are mostly flat shaded. They also do a lot of swapping of chunks of meshes where the normals of the swapped parts can join with a non destructible part of the mesh.

Olli.

hows this achieved?

as you can see the surface is perfectly smooth


now a part fell off.. how...

EDIT: and i've checked, its not pre-scripted since the cylinder falls apart differently every time

rube

In maya you can use "Normals>Average Normal" in the polygons menu

commander_keen

Its possible that they are doing truly dynamic booleans to break simple models like that. That would eliminate the prebroken normal weirdness. Its also possible that this object is pre broken but just done in a very smart way where the breaks all align to vertical topology lines, that way preserving the original normals would probably give a seamless result. They could also have a system to bake prebroken vertex normals into a texture use that texture instead of the vertex normals.

Olli.

yeah i just realized the object there might be normal mapped, which is something i cant do since my object is quite large and i need to use tileable maps.

I remember seeing someone make a proof of concept about procedural boolean breaking, so i might find that and try it out..

Pola

Haven't tried it out but if its a vertex normal thing, then wouldn't you just fracture the mesh the way you want it and then apply normal thief/transfer normals to it from a regular cylinder object? Then it should be able to break into pieces but still retain the appearance of a intact cylinder right?

Benton

This is Battlefield right? Frostbite 2 has its own mesh distruction system.

Olli.

could someone explain to me what all this spam is about? every thread i see has someone saying "thank you for your post"

Pola

Its a spambot, I don't know why the person is doing it or why they test it on an active forum like polycount. They get deleted but new accounts get made.