How to use Smart UV unwrap in Blender
Smart UV Project, (previously called the Archimapper) cuts the mesh based on an angle threshold (angular changes in your mesh). This gives you fine control over how automatic seams are created. It is a good method for simple and complex geometric forms, such as mechanical objects or architecture. UV unwrapping has many uses but it is mainly used for texturing a Mesh.
This controls how faces are grouped: a higher limit will lead to many small groups but less distortion, while a lower limit will create fewer groups at the expense of more distortion.
This controls how closely the UV islands are packed together. A higher number will add more space between islands. A lower number will pack the UV islands more closely.
Weight projection’s vector by faces with larger areas.
Map UVs taking the image aspects into account.
If the UV map is larger than the (0 to 1) range, the entire map will be scaled to fit inside.
Split the 3d viewport into 2 by left-clicking and dragging it from the corner of the 3d viewport.
Now on the top left corner of the screen click the editor’s type and change it from 3D viewport to UV editor.
Enter Edit mode on the other Window which displays the 3d viewport and select the whole mesh then F3 and it will open a search tab and type Smart UV project and set island margin to 0.3 (If you desire it to be apart) and press Ok.
Then click on the UV option and click Export UV layout and save the UV as a Png file that can be used to texture the mesh.