How to make long protrusion using sculpting?

Question

I want to sculpt a neuron using the Blender2.93 version. I am unable to make long protrusions using the sculpting mode. Should I go for modeling instead of sculpting?

I tried both Shake hook or Elastic Deform but it isn't working. The protrusions are supposed to be pretty long to represent a 1-meter axonal length. This is a structure I am referring to in 3D:

Another example:

Answer 1

The basic structure is modeled quite simply with a very little modeling, but with some modifiers.

Axons; this is basically one object with a Displacement modifier and cloud texture + Array modifier and Curve modifier to make it follow a curve (a Nurbspath in the example)

• create a cylinder, in Edit mode, add a few loop cut (Ctrl+R) to have more vertices for the Displacement modifier
• create a path, bevel it, and make the Axons follow it with an Array and Curve modifier (see for example Array instances do not follow the path of the curve and Problems with Curve Modifier)
• after the two modifiers, add a Bevel, a Subdivision Surface (level 1 is ok) and Displacement modifier. Create a Cloud texture for the Displacement modifier and adjust the Scale (very low, 0.08) of the Displacement modifier and the Clouds > Size value of the texture (0.09)

Nerve Endings are a tree with little spheres as leaves.

• this can be done either with a single vertex (default cube, M collapse) to create a "stick figure tree". Extrude E the vertex to create the tree and branches. Then add a Skin modifier. Adjust the thickness of the branches in Edit mode with Ctrl + T
• place spheres for the leaves. If you're lazy, duplicate the tree, and add and apply a Geometry Node modifier that uses Point Instance to place the spheres. After applying the modifier you can remove the unwanted spheres (hover the mouse pointer over the sphere, L, X, Vertices). The duplication is needed because the Geometry Nodes sadly don't work with the Skin modifier.

The result is shown at the bottom of the screenshot. The tree in the center has the modifiers applied and unwanted spheres removed. The tree at the top left is a sculpted version.

Alternatively, you can use Curves and bevel them, as done for the dendrite.

Dendrites; this structure is a "tree" made of Nurbpaths to have them more look like "split and bent".

• add a path and make it look like a tree. The branches are separate path segments in the same object because path/curves can't branch in Blender
• increase the Geometry > Bevel > Depth value in the Curve Properties settings to bevel the curve.
• in Edit mode create the pointed ends by Alt+A, 0 which sets the radius of the control point to 0.
• then Object > Convert to Mesh, and place & scale the branches properly. Scale up the base (Proportional Editing) and place the object at the world's origin along the y-axis (that's important for the particle system)

The result is shown at the bottom left in the screenshot, the correct layout in the middle. Make a few variations if you like and move them into a collection.

Sona, this is an icosphere (20 faces) with a Hair Particle System with the particles rendered as dendrites.

• add a hair particle system, 20 hair or less, select Emission > Source > Emit From Faces and 1 for Particles/Face
• Render > Render As Object or Collection, set Render > Scale to 1 and select the dendrite object or collection for Render > Object > Instance Object
• add a Subdivision Surface modifier, level 1, to smooth the edges

That's it.

For Sculpting you need to convert the hair particles to a mesh (button Convert at the modifier stack), then apply all modifiers top-down, and join the Sona with the converted particles (look for a new object called Mesh). Finally, apply a Remesh modifier or use the Remesh button in the Sculpt mode (does the same). Adjust the Voxel Size to preserve the mesh details.

Beware, don't use a too-small value for the Voxel Size or Blender will generate millions of vertices and freezes. You can halve the value and test it to determine the correct value safely. If wrong, undo and halve the value again.