why does my model look strange when it is smoothed? dark spots/shadows

[mbank]

hi
this happens with many of my models. i have no idea why. here is an example:
thanks
FLAT:

SMOOTH:

[Richard_Marklew]

Looks like some face normals pointing the wrong way. Select all vertices, remove doubles (W / remove doubles) then recalculate normals (Ctrl+N)

[mbank]

thanks, this kind of worked, it took the problematic area off the top of the model and put it on the bottom. i will try deleting the faces and making new ones.

so what did i do wrong when modeling this that made this happen?

[kastoria]

@mbank

thanks, this kind of worked, it took the problematic area off the top of the model and put it on the bottom. i will try deleting the faces and making new ones.

so what did i do wrong when modeling this that made this happen?

You just had bad luck. With every face that get’s added, Blender has to decide which is the front side and which is the back side. It probably does this based on faces that already exist and maybe your method of adding the face (i.e. extrude probably works differently than adding 4 vertices then creating a face on them).

If you knew all the rules then you might be able to model something start-to-finish without getting some normals reversed, but that is way too much to ask a human to worry about. Just model and correct the normals when you have to.

If hitting the “recalculate” button does not fix all the normals then you can highlight the faces that are broken and “flip normals” to just adjust those faces.

[mbank]

@kastoria

You just had bad luck. With every face that get’s added, Blender has to decide which is the front side and which is the back side. It probably does this based on faces that already exist and maybe your method of adding the face (i.e. extrude probably works differently than adding 4 vertices then creating a face on them).

If you knew all the rules then you might be able to model something start-to-finish without getting some normals reversed, but that is way too much to ask a human to worry about. Just model and correct the normals when you have to.

If hitting the “recalculate” button does not fix all the normals then you can highlight the faces that are broken and “flip normals” to just adjust those faces.

thanks for that info.

i was using the shortcut “f” to create faces a lot, and dragging the vertices’s around in between, and merging a lot of stuff, thats probably what caused it. i will stop doing that junk and just extrude and scale and move when that is sufficient. thanks!