Normals from ZBrush to Maya, issues

Fragdady

So I've been working on a chair in maya. I brought it over to zbrush and made a high poly version and used xnormal to get the normals. I exported each subtool separately to correspond with the different objects in maya (the wheels, chair back, cushions, etc.) I have the low poly model uv'd.

Some parts of the chair look okay, but there are a few areas that are messed up. Does anyone know why this could be happening, and what I could do to fix it? Sorry if this isn't the correct place to post this.

Thanks for the help.

Fragdady

I figured out if I bake out the normals for just one piece, like the seat cushion, it'll get rid of the tearing. So I could just do every piece individually and combine the different normal maps into one but I'm thinking there has to be a better way.

AdvisableRobin

Are you baking with a cage? If not, I assume you are baking in Maya, under the target tab turn the display to both and then modify the search envelop slider until the mesh just envelops every part of the highpoly.

JedTheKrampus

You could get a similar effect (baking the normals without any artifacts caused by intersections with other high-poly parts of the model) by exploding your low-poly and high-poly models. Depending on how you did the sculpt there are a couple of ways to do it. If you worked exclusively with multiresolution subdivision in Zbrush, and you don't have any custom normals from Maya that need to be exported to Xnormal, find the Xpose button and click it. This will move each subtool apart to a distance that will work for baking maps. After you've clicked this, use the subtool master plugin to take each subtool to its lowest subdivision level. Export all the subtools at this low resolution, then use the subtool master plugin to take each subtool to its highest subdivision level and export all the subtools again. Put your cage together in XNormal and you'll be all set.

Of course there's no way to set hard edges or anything with this, so this method is somewhat limited, especially if you want some hard edges on your UV seams to deal with non-synced tangent bases or texture compression or low-resolution mipmaps, or other custom normals, and the lowpoly model won't be triangulated so you'll need more polygons in your low-poly model to deal with artifacts. Depending on what your workflow is this might not be a problem, but things are probably not in your favor for using this method. It's just easier when it works, so it's worth mentioning. The other, more flexible way to explode your bakes is to put all your lowpoly meshes on a layer in Maya and use the Decimation Master plugin to export a decimated version of your highpoly model to Maya. Hide your lowpoly meshes and add your highpoly meshes to a new layer, then select each piece in both its highpoly and lowpoly versions, set a keyframe for their locations, go ten frames forward, move both the pieces, and set another keyframe for their locations. Move back ten frames, rinse and repeat for each piece (sometimes you can speed things up by setting keys for a few pieces at once, since as long as they're not too close to each other you won't have problems.) After this, deselect everything, go to your exploded keyframe, hide the highpoly meshes, select the lowpoly meshes, and export everything in a .fbx. Then deselect the lowpoly meshes, hide the lowpoly meshes, show the highpoly meshes, select the highpoly meshes, and export everything in a .fbx. At this point you should be able to make the cage correctly for your lowpoly in Xnormal's 3D viewer (no custom cage tweaking pls, just push everything out uniformly) and bake the normal maps in one go.

THAT SAID, I would STRONGLY encourage you to model your lowpoly more contiguously in the future. If more of your lowpoly model is in one piece, you won't need to spend as much time exploding as you did before! Just keep in mind whether any of it needs to be animated (e.g. the chair spinning on its axis or rolling across the floor) and keep in mind what parts might need to be separated for that. Everything else should ideally be in one chunk. You'll reduce overdraw, spend less tedious time getting your bakes ready, and overall be a happier person the less you have to do special preparation for bakes.