Orientation on normal maps

[daxxx39]

Goodevening, first I ask sorry if my post will be not so clear, cause of my bad English.
I have a problem with generating normal maps with multi map exporter.

I notice that the orientation in the UV map make change the result in the normal map.
An example, if I create a normal map, with the UV island in the UV map made in one position, then i rotate the uv map, the normal look invert, when i import in substance painter for example, it give different result, the up direction become down.
I though the rotation of uv island in the uv map did not inflence the result of normal but in true it does, am I correct?

Another example for try to explain me, sorry guys my language.
If I have a mesh, and i make the normals, i have a result, if i flip V the UV map, the normal will be totally different, and when i use the normals maps somewhere else, the diretion of normals look also invert… so flipping , rotating etc the UV map give different normals… thank you for your patience on reading

[daxxx39]

Maybe an example I can be more clear, look this 2 uv maps, same object, just the panel is rotate of 180°. the normal that will appear in zbrush will look different, if I will apply this normal in other 3d software az substance painter or 3ds max, it will give different result, but why? The creation of normal map should be indipendend from how I arrange the uv map, isn’t?
Thank you!!

[Spyndel]

Hello @daxxx39

Different programs reckon their worldspace differently. Multi Map Exporter is set to flip maps vertically by default. You can adjust these settings to suit your target program. Flipping the orientation of your UVs will affect texture display.

[daxxx39]

Thank you for the reply, Spyndel, I saw that for default it flip the map, what i was wonder that the map create when uv is in one orientation, and in another, the result is very different, from the example i show you before if a crease is up in one, in other look like go down (i mean when I apply in a 3d model with a 3d software).

I belived thatoritentation on uv was not important , thank you fro answer, i need be much more carefull how i make my maps, it give me less possibility to optimize the usage of space, becausea all the maps in uv space must have same orientation.