Sometimes during our digital 3D art project we may find ourselves when we have stretching textures.
A texture gets stretched to its limits when the corresponding UV map has no area. This may happen if we create new geometry on an already UV unwrapped and textured object. To solve it, UV unwrap the new geometry.
Let's look at some tools that we can use to prevent this from happening and some fixes for when it does.
If our texture is already stretched, we need to adjust the UV map that describes how the texture is projected on to our 3D model.
For a full guide on UV mapping, you can read this article:
Related content: The definitive tutorial to UV mapping in Blender
For simpler objects you can follow these steps:
Blender will cut the UV map according to the settings specified in the smart UV project settings. The defaults work in most cases.
Instead of selecting your entire mesh, you can also select just the areas that are stretched and unwrap them again separately, still using the Smart UV project or try the regular unwrap method.
You can then move over to the UV editor where your selected faces in the 3D viewport that are UV unwrapped will show.
You can use the basic selection and transformation tools we have available in the 3D viewport to adjust your UV map further.
To get real-time feedback and see how your applied texture changes, make sure you are in material preview mode in the 3D viewport.
If your object is more complex, such as an organic model, we need to work with what we consider the manual tools to unwrap. You need to plan where to put your seams on your model so that they are as hidden as possible.
You must also use as few UV islands as possible to minimize the number of seams.
You can get some visual help from Blender to see how your UV map is stretching. In the UV editor header on the right side, there is a UV Editing drop-down menu. You may have to middle mouse click and drag the header to see the menu.
Open it and check Display stretch. You can view stretching by angle or area.
More blue colors mean less stretch, while yellow means moderate stretch and red shows severe stretching.
If we have already applied a texture to our object but we still intend to continue model it, we can prevent textures from stretching in a few different ways.
The "correct face attribute" option will create new UV space for newly created geometry with accordance to the surrounding mesh and UV map. Follow these steps to enable it:
As we create new geometry, for instance, by extruding the UV map will correct itself accordingly.
When we insert new mesh within the existing topology through the loop cut and slide tool, the UV map doesn't get affected if we don't slide the loop cut. But if we slide it, you see the UV map stretch along with it.
To avoid stretching as we use loop cut and slide, go to the operator panel in the lower left corner, then check Correct UVs.
The loop cut and slide tool will now leave the UVs as they were before sliding the cut.
The last item on the list means that we skip UV mapping altogether and instead do a box projection of our texture. To find out more about how we can do this and the benefits and limitations, you can read this article:
Related content: Blender box mapping workflow, a quick look
In this article we looked at what we can do to fix already stretched textures and making sure that we don't end up with a stretched texture.
With this knowledge, we should be able to have textures on our models as we model if we wish without too many problems.
Thanks for your time.