4.13 - Auto Generate Collision and LOD Screen size not working?

Hey all,
So I’m super excited to be using the latest version of the engine again after being glitched out of upgrades since 4.10. Only thing is that I’ve noticed that a few of the features of the model viewer don’t work anymore. If I want to auto generate a collision mesh for example, when I open up the auto convex collision window adjust the settings and hit apply, nothing happens. I have to actually open up the detail panel, check off auto generate collision and then reimport my mesh for it to work. Also strangely enough all of my meshes that I brought in from 4.10 are showing two wires when I turn on collsions… a purple one that shows the collision mesh and then one that’s baby blue that looks like the entire mesh’s polycount. Just curious what that is.

The screen size LOD setting also seems to have zero effect. I’ve only got one LOD, but its disappearing when you get more than a couple units away from it. I’m creating a short grass mesh using the method as described in this post (Ryse Moss Tutorial — polycount) where you stack multiple planes on top of each other at a very close distance. If I scale up the texture so that each “blade” of grass is thicker, it renders fine but obviously this is less than ideal. The mesh itself is 200 x 200 units in size so it shouldn’t be too small. I set the screen size to 0.2 which is what the current screen size value was at where I want to be able to see it but it had no effect. I’m wondering if this is similar to the auto collision not working unless I turn it on and re-import… is there something I have to do to “jump start” the editor into realizing I’ve changed the value?

There’s no chance that distance based LODs are going to be implemented any time is there?

Hello TorQueMoD,

I have to actually open up the detail panel, check off auto generate collision and then reimport my mesh for it to work.

If you have previously imported meshes, and you had the ‘Auto-Generate Collision’ enabled, then what you are seeing is expected. You can either go the re-import route as you mentioned, or you can select the ‘Remove Collision’ and then use the ‘Auto Convex Collision’ options and apply the modified collision.

Also strangely enough all of my meshes that I brought in from 4.10 are showing two wires when I turn on collsions… a purple one that shows the collision mesh and then one that’s baby blue that looks like the entire mesh’s polycount. Just curious what that is.

Yes, that is the meshes wireframe as well as the collision being shown. The wireframe is shown because you can use the per poly as collision, so being able to visualize that is important.

In regards to your LODs not working based on screen size, can you provide me with some screenshots and steps so I can reproduce the issue on my end. All the meshes in my projects are working as expected, so I need a way to reproduce the issue on my end.

Let me know if you have further questions.

Cheers,

Hi Andrew,

So for the LOD issue, this is what my mesh looks like:

It’s a series of planes (32 I think) stacked on top of each other very close together as shown in the bottom left inset. Using the alpha texture shown, it creates the look of 3D grass. Problem is, once I add the texture, it thinks the mesh is too small and doesn’t render it correctly regardless of what I change the screen size to. Both the mesh without a texture and the mesh with the grass material applied are at the exact same distance fyi. As soon as the material is applied, 90% of the mesh is culled.

As for the auto generating collisions, I’m having the issue on newly imported meshes as well. Back in 4.10 I used to be able to bring up the tool, hit apply and it would create a collision right away. Now I have to do the work around as I said by checking off auto generate and then re-importing which ends up taking longer.

Thanks for the help!

Actually, it seems the auto generation is working again as normal. Maybe it was just a glitch with that time I loaded the editor. LOD is still a problem though.

So what about the LODs?

What you are trying to do is not a typical workflow that is supported by the LOD system out of the box, and it is expected not to work. You will need to use custom code and modify things like the bounds scale of your meshes for everything to draw correctly.

This approach, especially with the number of planes you have stacked on one another could quickly cause overdraw, become non-performant, and have a number a rendering issues due to the fact you are using opacity masks and translucency which depend on sort order when drawn on top of one another.

Since your planes are stacked so closely together for this approach, and LOD changes based on screensize, those will all be changing at different points when you are drawing the mesh at any distance, this is because they are not all occupying the same screenspace. As I mentioned, this is not expected to work out of the box with our LOD system, and you will need to write custom code for this to work as you expect.

Thank you,