To assign mapping coordinates for each material, we select the corresponding faces.
In Surface Properties Material, Mesh Edit or Poly Edit click on Select by ID.
The Material ID is the number of the sub-material applied to the object.
Here there are 5 Materials ID and the blue material has for Mat. ID 2.
Apply UVW Mapping.
3d uses XYZ for coordinates the objects, for the mapping coordinates UVW are used.
By default, Planer projection is that will work well as it is what we need here.
Note the rectangle which appears in the viewport, it is the representation of the projection that the mapping coordinates use.
By default, max dimensions objects with the dimensions of the selection with planer mapping.
We will set the same values in Length and Width to have a square projection.
Indeed it is necessary to provide a square texture and if possible in the dimensions of 128x128 pixels, 256x256, 512x512 etc.
For optimal use RAM it is preferable to use these dimensions.
To see the texture applied in the viewport, activate the Show Map icon.
This should be activated for each material applied.
The representation of this rectangle in mapping is called a Gizmo in max.
If we Edit in sub-object mode modifying UVW Mapping by selecting the Gizmo, this becomes easy to handle just like a simple object.
We can now edit the Gizmo with all the normal editing Tools such as Scale, Rotate & Move.
The orientation of the mapping is given by the green feature for the axis of U and by the yellow segment for V, the W axis is perpendicular.
Rotation the Gizmo on the Z axis.
The texture follows this rotation.
To cancel use Ctrl Z.
Also while holding the Left Mouse Button if you tap the Right Mouse Button, this will Cancel your current edit. This works for all editing within max.
To continue mapping the object, for each Material ID select the corresponding faces then apply mapping coordinates. (also called UV to make it shorter).
Apply the modifier Poly Select or Mesh Select according to the nature of the object.
The oranges faces have Mat. ID 3, therefore enter 3 then Select.
Apply UVW Mapping.
And change to Cylindrical Mapping.
Cylindrical Gizmo appears but it is out of proportion with the dimensions of the selection.
To set it to the right dimension, click on the FIT button. "Upper Left Pic"
Apply the Orange faces with the Checker material.
As for the Gizmo, a green reference mark indicates were the mapping joins itself.
Apply a rotation to make it coincide with the middle face. In this case about 90 degrees.
Note that the checker is completely deformed because the object is not cylindrical.
Nevertheless it is still this type of projection which will allow your mapping to conform quickly here.
Correct the mapping coordinates with Mesh Edit or Poly Edit on a traditional object.
Collapse the Stack.
Ensure that the Object has Collapsed and apply Unwrap UVW.
Click on Edit...
The UV editor opens and the object lines appear.
These lines correspond to the mapping coordinates assigned with each face.
If they do not have any, max puts anything in their place.
The checker corresponds to the texture of first Sub-Material of the object.