Smoothing problem in Zbrush

salimmatta

Hey guys,

So as you can see below, in maya the house roof looks fine until I import it to Zbrush, any idea why is it happening and how to solve it?

(note: I can manually smooth it in zbrush but I don't want it to affect other parts of the house, besides, it will be time consuming)

goekbenjamin

in maya maybe the edges are set to soft edges?

Alex_J

zbrush viewport doesn't display softened edges for the sake of speed. When you export it you can set it to export with smoothing groups. 

salimmatta

goekbenjamin said:

in maya maybe the edges are set to soft edges?

If set them to soft or hard edge, still get the same results, any idea if there is a way to import it to Zbrush exactly the same way as maya?

salimmatta

BIGTIMEMASTER said:

zbrush viewport doesn't display softened edges for the sake of speed. When you export it you can set it to export with smoothing groups. 

I did mate, still same results, it is really frustrating, im pretty sure there is a way to be imported exactly as maya, cheers for the help!

Internet Friend

It is the same as in Maya, ZBrush just isn't hiding information. You need to make a version of the house with support loops or creases you can subdivide and sculpt on for ZBrush. 

musashidan

Zbrush doesn't use goraud smooth shading. There is an old-school hack to simulate it but it isn't the same.

gvii

If you are looking to start off the sculpt in Zbrush using the low poly model you have a few options:
#1 - Dynameshing the pieces at a decent resolution so you can remove polygon face detail easily without affecting large shapes.
#2 - Adding creases before subdividing either inside Zbrush or in Maya.
#3 - Adding beveling and topology that supports the subdivision (You can test how the model will smooth out in maya before bringing it to Zbrush).
#4 - Bring in a smoother, presubdivided model from maya before starting the sculpt.

Like someone has mentioned before, the only way zbrush does "Smooth Shading" is with higher polygon counts. So there's no actual way to smooth normals as we do in maya.

Alex_J

For now, you can consider it the same model. And keep in mind, the only thing that matters is your final export in your render engine. So reapplying smoothing in maya is something you can do at any point. It doesn't matter then if zbrush isn't recognizing it.

But to understand what is happening, you need to study subdivision surface modeling more, and also what normals are, and how they work. Probably the wiki here has most or all of the information you'll need.

cryrid

A little more explanation on what Zbrush is doing:

Zbrush doesn't render 3d models the same way a program like Maya does. This is because zbrush isn't a full 3d environment that has cameras or lights physically positioned around the model to work with. It's just a model floating above a static 2d painting canvas. When you navigate in zbrush you're not orbiting a camera around a model, you're basically spinning the model itself as it floats there. 

Zbrush fakes its materials by pulling information from an image of a sphere. It will look at whatever direction a single polygon on your model is facing, match it up to the whatever pixel on the sphere-image is facing the same direction as if the sphere were a real object on the screen, and take the color information from that specific pixel on the image. It does this for every polygon on the model. This leads to the faceted appearance, especially with a lowpoly model. This behavior doesn't change even when you subdivide the model, tthe polygons simply get smaller with a more gradual blend between the planes / normals thanks to the geometry itself getting smoothed until the polygons become so small your eyes can no longer distinguish between them. The other side effect to this method is that its all screen-space too, so if the image of the sphere appears to be lit from the top left, the model will appear to be lit from the top-left of your screen no matter how you position it. 

This material system is simply how zbrush displays the model, and isn't part of the model data itself. If you export the model and load it back into Maya then you'll see it appear smooth again since Maya renders differently and will blend its shading across vertex normals. 

Ros2792

In ZBrush:
Render Properties - SmoothNormals

http://docs.pixologic.com/reference-guide/render/render-properties/