Questions about normal map creation

Unreal Engine Asset Creation
#1

Here is a guide for normal map baking for Unreal 4:

I could follow it, but i’d like to understand it. Also I’m a Blender user, so if possible try to explain it in a way so i can get my models from Blender right.

Questions:
(fbx export)
1, One smoothing group? Does it mean that the whole model is smoothed and no hard edge? (Blender smooth shading, no edge split)

2, tangents and binomials option unchecked. What does that switch does? what would happen if i left that on?

in xnormal
3, says ‘use exported normals’… but in this case i gues they are same as averaged normals, right?

Unreal engine specific
4, what do these options do? import explicit normals checked, import tangents unchecked.

Thanks

#2

I think that page will be update for UE4.1, currently it’s not correct: Normal Map Workflow with Xnormal is not working - Programming & Scripting - Unreal Engine Forums Also read this:http://www.polycount.com/forum/showpost.php?p=2039738&postcount=1404

  1. Yes 1 smoothing group, no hard edges.
  2. Unless blender can write out tangents and binormals , I suggest leaving that unchecked to follow the baking workflow.
  3. used exported normals is not the same as average normals. using the exported normal from the FBX as opposed to let Xnormal calculate its own normals. You want the normals to be the same as your 3D app, that’s why you should always use “use exported normals”, or else you might get baking errors.
  4. Those are old setting they aren’t applicable to UE4, the new docs will go up and update the proper settings to use. I think the docs are from the old UDK document and it required exporting to FBX 2006(and I had to let UDK calculate the normals) to get the workflow to work at least that’s what I tried in Modo to UDK last month.