Blender Skin Modifier: The Alternative To Traditional 3D Modelling

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    Blender’s skin modifier is useful for creating “base” meshes for sculpting or organic shapes that are smooth in nature (such as skin).

    It can also be defined as a skeletal deformation tool which makes it perfect for character creations for animations. Rather than updating / editing the mesh of the model, it is controlled by the inner skeletal of the 3D model.

    Extruding blender skins
    Part is automatically generated through the extrusion of a single vertex when using the Skin Modifier

    Modelling A Hand With Skin Modifier

    In this example, we’ll be using the skin modifier to model a human hand. The idea is to demonstrate the flexibility of this modifier over say, “traditional” means of modelling and extruding.

    The skin modifier is not a replacement of traditional modelling, but under certain applications, provides far more flexibility and swiftness in modelling.

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      In fact, I see the skin modifier as a combination of Bezier curves following a path and traditional modelling of extruding meshes and surfaces. It can be flexible for model creations and fast for editing purposes!

      Step 1: Load Default Cube

      When loading Blender, the default cube will appear.

      Go into edit mode, select all vertices except one.

      Deleting default cube ready to use skin modifier

      We now have a single vertices in our scene!

      Single vertex ready for extrusion

      Step 2: Extrude Vertices

      While still being in edit mode we want to extrude the vertice along the z-axis.

      We do this by hitting “E” for extrude on the keyboard, then “Z” for z-axis.

      Now move your mouse to extrude the vertice so it looks like the image below:

      extruding base model for skin modifier

      Step 3:Applying Skin Modifier

      Now we have to come out of edit mode and into object mode.

      before applying skin modifier, we must be in object mode

      After that, we apply Blender’s skin modifier which we do by following these steps:

      1. Click on the modifier tab (the one that looks like a spanner)

      skin modifier is under Blender's modifier tab

      2. Next, click on Add Modifier > Skin

      Applying skin modifier to commence base 3d model

      3. Notice, your two joined vertices now turn into a solid elongated cube.

      4. Next we want to subdivide the model to make it rounded smoother

      subdividing part to give it smoothness

      Step 4: Building Up The Hand

      The current object will act as the palm of the hand, and now we want to work on creating the first finger.

      1. In edit mode select the top vertex.

      selecting vertex on Blender in edit mode

      2. We want to extrude the vertex & move it upwards and to the right.

      Hit “E” on keyboard for extrude, and simply move your mouse to create the following finger.

      further extrusions while on skin modifier

      3. Follow the same steps to create the remaining 3 fingers and thumb.

      base human hand model using skins

      It doesn’t look much like a realistic hand, but it is the base model of a hand. We will be working a little more on it to make it look more realistic!

      Step 5: Scale Vertex On Skin Modifier

      If we look at the palm of the hand, we want to enlarge that, because at the moment it looks too small and a little off.

      We achieve this by sort of scaling the vertex in that regain.

      Select the Vertex > Ctrl+A > Move mouse outwards

      tweeting palm of hand by scaling vertex point

      Now we want to follow the same process for creating the wrist area!

      tweaking wrist by scaling vertex

      Although far from looking realistic, we can see it is taking shape and shouldn’t take too long getting it to look right with some tweaks.

      Step 6: Tweaking Vertices For More Realistic Hand

      Here we simply move the vertices about to form a more of a realistic looking shape hand.

      For example, I elongated the middle finger as it is the longest on the human hand. Then I lengthened or shortened the other fingers, while bending the thumb in a curved manner.

      So far I managed to achieve these results by moving the vertices around! ↓

      refining the fingers of a human hand

      Step 7: An Other Scale Trick For Skin Modifier

      If you feel your fingers are a little too fat in relation to the whole hand, you are able to scale them down.

      Note: A single vertex cannot be scaled down using the “S” command on the keyboard. However, multiple vertices selected can be scaled down.

      To achieve thinner (or thicker) fingers, select the vertices that make up the whole finger on all fingers as shown below. So far I managed to achieve these results by moving the vertices around! ↓

      scaling trick for skin modifier
      1. On the keyboard hit Control+A and move your mouse.
      2. Moving your mouse one way will make selected areas fatter.
      3. Moving your mouse the opposite way will make selected areas thinner.
      Scaling trick number 2 for skin modifier

      Step 8: The Final Result

      I would encourage you to further tweak the vertices to further improve on the realism of the hand.

      You can try:

      • Moving selected vertices (“G” on keyboard)
      • Rotating selected vertices (“R” on keyboard)
      • Scaling selected vertices (“S” on keyboard)

      This is my final result for a base hand, which will now need sculpting to bring further realism.

      Base model of human hand

      Step 9: Apply Skin Modifier

      The very last step would be to apply skin modifier and the subdivide modifier

      What this does is convert your model into a mesh.

      From skin modifier to mesh

      Blender Skin Modifier Shortcuts

      As seen, there are several steps to creating an organic model such as the human hand. Much of the instructions on this article provide shortcuts, such as using hotkeys on the keyboard.

      However, out of all the shortcuts, I would say the most important & most powerful hotkey is Control + A (shown Step 7). This adjusts the resulting Skin scale of the selected vertices when in Edit Mode.

      Further control of the scale direction can be had by then pressing “X” (x-axis) or “Y” (y-axis). This will force the model to scale in the direction of the selected axis.

      Closing Thoughts

      If like me, I would have tried creating the human hand using traditional means of modelling. By traditional modelling, I mean, starting of with the default cube, creating loops and extruding various areas of mesh to acquire the desired results.

      The only problem, I was never able to get the “desired results”. That was because I took the wrong approach from the start and should have used the Skin Modifier (had I known it existed).

      In honesty, although my hand is not the most realistic, it was the first time creating one using this method, and I did it while writing up this article… and if honest, I am pleased with the results!

      Blender never fails to impress me with the abundance of features it has (and keeps adding) to its arsenal. So the next time you want to create an organic looking model, consider the skin modifier.

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