Smoothing group issue?

3DRyan

I already posted this on the UDK thread, but got minimal responses, so I'm trying it here. If you look at the pic, you'll probably know what's wrong:



I think it's a smoothing group issue. I used maya to model the leaves, and it's all geometry. No alpha at all. Anyone know what might be causing this? If it IS a smoothing group issue, how do I fix it? I've tried both smooth and hard groups, along with all the tools under "normals" to change around the normals. Like I said, this pic is showing it in the UDK editor. Anyone got an idea?

Eric Chadwick

First of all, if each blade is its own mesh, that's way too detailed for most games to handle. You should be using alpha maps.

Secondly, flat geometry in general is going to shade badly. One way to solve this is to bend the vertex normals so they point in a dome-like shape. Was this made in 3ds Max? You can use the Edit Normals modifier to do this, or the Normal Thief script to automate it a bit.

Eric Chadwick

Found an example I made recently to play with vertex normals. Might help you visualize what I'm talking about.
http://boards.polycount.net/showpost.php?p=1122194&postcount=34

Will Faucher

He said he was working with maya, Eric.
But I agree with flat geometry shading badly, not sure how you could change it in Maya though. I'm totally new to maya.

Eric Chadwick

Ah, ok.

The Vertex Normal Edit Tool might help then.

mayaterror

Eric, could you or anyone else post some more info about using this Edit Normals modifier? I've always scrolled right past that one, never knew what it did. My mind is really spinning around the possibilities for how much better my models will look with this. I'm going to check out this NormalThief script and read the Max help on Edit Normals right now...

Eric Chadwick

Yeah it basically lets you modify the directions of the vertex normals. They control how each corner of each triangle will be lit, you can do some cool things with it.

Works great for evening the lighting on planar foliage.

Works great for killing the lighting seam between two adjacent meshes, like for example if terrain is split into quadrants, and they join seamlessly except for the lighting, then you can select both models and apply a single Edit Normals modifier, then average the edge normals so there's no lighting seam anymore. Woop!

Also works great with reflection maps, like if you have a fairly flat mesh like a car bumper but you want it to reflect more, then you can bend the edge normals further outwards, so the triangles then pick up more of the reflection map.

Also there's the super-specular thingy, bending the normals so bevels look sexier.

One thing that pissed me off is how the normals get reset if you do certain things in Max, like rotating a model then attaching it to another. You have to do a Reset Xform first, to both meshes.

kdm3d

yeah... max resetting those sucks. How clean and easy would normal bakes be if we could control the normals on the low poly, THEN ad the projection modifier on it... that would be too cool though.

sprunghunt

EricChadwick wrote: »

Yeah it basically lets you modify the directions of the vertex normals. They control how each corner of each triangle will be lit, you can do some cool things with it.

However since he's using the UDK this won't work - since custom normals don't work in the UDK.

What he should do is render the plant to planes and then use a foliage factory or foliage layer. This should use the custom foliage lighting that come with these systems that will fix a bunch of the problems usually associated with foliage normals.

3DRyan

Hey all, sorry about the late response. Long day at work. Okay, provided that UDK won't allow custom normals, how do I "render to planes"? Also, the plant mesh is already in a foliage layer and the lighting seems to be the same as when I place it as a static mesh. Is there a setting that needs checked for it to use foliage lighting?

Thanks for all the responses, everyone. I appreciate the help

Eric Chadwick

Render to planes...
http://www.andyzibits.com/tut_maya_low_poly.html

3DRyan

Cool! Thanks for the link, i guess the only thing to take from this is to make the edges of my leaves quads and use an alpha? I'll try this.

Eric Chadwick

I wouldn't simplify all the advice down to just that.

It looks like in your original image that each grass blade was its own piece of geometry. Is this so? Instead usually games put several blades in one map with alpha, and UV that onto a plane (or simple bent shape), much like the branches in that last tut.

3DRyan

Ah, gotcha. Looks like I'll have to do some thinking on how to apply the same logic to this kind of plant, but I bet I can manage it. Thanks for the help, EricChadwick.