Hello guys! Brand new here, and this is my first post! Anyhow, I’m having some problems with something I’m working on. Basically, I’m trying to achieve a goal where I can use seamless map pieces to sort of build together my my level. Opposed to building everything in blender and importing it as a bunch, since that didn’t play well with lightmaps. My main problem here though, is the fact that there’s a noticeable change in shadowing between the map pieces. You can see below how bad it is, and I’m currently stuck with no solution so far on fixing it. I’m also a UE4 noob so talk to me like I’m five.
Another problem, which may be more easier to fix is having smoothing issues. Basically, I’ll make my smoothing groups and what not in blender, but when I export them over (FBX) they don’t carry. Instead, I get the “No smoothing groups found”. I’m sure this is more of a blender based problem, but if anyone can help me out that’d be very much appreciated.
It’s probably because the shading is smoothed. When you create an object in Blender, you can shade it in two ways. You can have it flat, in which case each face is a ‘facet’ with sharp edges. Alternatively, you can have it smooth, in which case the angle used in lighting computations is smoothed across the edges. This creates an object which looks smooth even though strictly speaking the shape of the object hasn’t changed.
Now imagine you create a smooth-shaded cube and import it into Unreal. You put two of these cubes adjacent to each other, and run Lightmass. The shape of these cubes is right, so they do butt up against each other without leaving a gap. Unfortunately the angle used for the lighting varies across the face, because it’s shaded as though it were (approximately) a sphere. This leads to an effect where one cube is bright adjacent to the join, and the other one is dark, so you see a discontinuity.
As if this weren’t complicated enough, there is another issue, which is that Unreal can optionally recompute normals on import. This means that something which is smooth-shaded in Blender can end up being flat-shaded in Unreal, or vice-versa.
Can’t answer to 1st question. But about smoothing error in UE4 when importing, when you exporting from Blender make sure you chose ‘face’ option from smoothing setting
By default ‘normals only’ selected. With ‘face’ option you will not get that smothing group error when importing to UE4. But with this setting there will not be any hard edge in your mesh if you need(If you did not already split that edge where you want hard edges). So what I am doing in this situation, creating mesh in blender, exporting as FBX without smooth shading (neither inside of blender and not when exporting). Then I import that FBX mesh again and clearing sharp edges which is green by choosing that edge in edge select mode and pressing ctrl+e where I want smooth shade. After that I export again not touching anything about smoothing anywhere.(Do not like split edges in blender, do not know why :)) And when I import to UE4 in import menu I chose import normals instead of compute normals.
