After scaling and positioning your t-shirt mesh, begin applying sculpting detail to add cloth and fabric details. While there are many ways to sculpt an object in Blender, this tutorial primarily uses the Elastic Deform, Inflate, and Clothing tools to make your mesh look more like a realistic t-shirt.

To add clothing details:
With LongSleeve active, switch to Sculpt mode.
In the top right corner of the viewport:
- Disable Wireframe mode.
- Enable X-Axis symmetry to perform symmetrical edits.
Select the Elastic Deform tool at .5 strength to stretch parts of vertices to completely cover the mannequin.
Use F to change the radius of the brush.
Hide the mannequin to access hard-to-reach areas.
Select the Cloth tool, then:
- Disable X-Axis symmetry. The Cloth tool can produce unexpected results with symmetry enabled.
- Click and drag on your mesh to add a cloth-like surface to your mesh. Adjust the settings to change the strength of the deformations.
Using the Elastic Deform, Inflate, and Cloth tools, make the final adjustments to your mesh so that it sits on top of the mannequin with the final desired shape.