Making Tentacular Horrors!

I love making tentacular horrors in Blender.  Through the use of a few relatively simple curves, you can easily make complex, tentacled monsters, which is really fun!  Using this method, a tentacle will be made up of 3 parts:
  1. A Circle that defines the cross-section of the tentacle (called the Bevel in blender)
  2. A Curve that defines the Taper of the tentacle
  3. A Curve that defines the pose of the tentacle
First, I like to start with the cross-section circle.  To make this, I just press Shift-A then go to Curve -> Circle to make myself a nice round circle.  If we want this tentacle to be malformed in some way, we can edit that circle, but for now, let's just keep it round.

Next, I make the taper curve.  You can use either a Bezier Curve or a Nurbs Path for this and I'll bounce back and forth between the two depending on how complex I want the taper to be or just how I feel like manipulating the controls for the curve.  When I'm making a taper for a tentacle, I usually want it to be fairly thick at the base and then gradually taper downwards to a fairly fine tip (tapering more sharply near the end).  In this case, I wanted the tentacles to have ridges, so I made my taper curve a bit more complex.

So, to make this taper curve, I hit Shift-A then went to Curve -> Nurbs Path to make my path object.  A Nurbs Path has 4 points when you create it.  If you go into Edit mode, you can manipulate those points to change the shape of the path.  Since I wanted my tentacles to have all of those undulations in them, I needed more control points.  I selected the whole path and pressed w, then selected subdivide and increased the number of cuts to 10 so that I'd have a bunch of vertices with which to work.  I then subdivided it again, because I wanted these guys to be super wavy!  With all of those vertices created, I selected every other one (I wish I knew a clever way to manage that...), then slid them upwards a bit to make a sine wave.  Then, I decided that I wanted to reduce the amplitude of the wave towards the end, so I pressed O to turn on Proportional Editing and then selected the end two vertices, pressed S for scale (mouse-wheel to adjust the size of the circle of influence) and then Y to limit it to the Y axis (that's the axis that is the amplitude of my sine wave).  I scaled down the distance between those two points, which proportionally scaled the amplitude of the whole wave.  Finally, I selected them all and rotated the whole kit-and-kaboodle so that the wavy tentacles would be larger at the start and trend towards smaller tips.

Whew.  That was quite the block of text and took quite a bit to describe, but was actually a relatively simple operation to make a nice complex taper for my tentacles.  So, let's spice up the post a bit with a Before/After screenshot!

The set of tentacles on the left is just the curves.  The one in the middle has the circle bevel but no taper applied to it, and the one on the right has that decaying sine wave taper that we just built!  Setting this up is super easy, which is one reason that I love this technique!

With the bevel and the taper defined, the next step is to build the curve that the tentacles will follow (the left-most image in that screenshot).  In this case, I made the tentacles by hitting Shift-A and selecting Curve -> Bezier, but I think that I'm going to use Nurbs curves more in the future because they're just a lot more intuitive for me.  Still, I used a Bezier here, so you can see that this particular tentacle is defined by 3 points and their handles.  The Bezier curve will always pass through those 3 points, but those handles effect how it approaches and exits each one.  By tweaking those handles, it's really easy to define a windy organic tentacle path with very little work!  Even better, it's super easy to tweak that tentacle's path to change the overall look of the monster if you don't like how something's lining up!  So, I added and posed a bunch of beziers/tentacles (5 in this case), then finally got to use those bevel and taper objects that I created!

Applying the bevel and taper objects is super easy.  With the curve object selected, go to the Curve Data tab (the little icon that looks like a curve).  There's a bunch of cool stuff in here that controls how that curve is rendered, but right now, we only care about three things (all in that Geometry section): Taper Object, Bevel Object, and Fill Caps.  So, you just have to select the appropriate objects for each of them, either by browsing the list of available objects or by using the eye-dropper and then clicking on the actual object that you want to use.  Enabling Fill Caps instructs Blender to make appropriately sized discs at the end of each tentacle, otherwise they'd be 2-Dimensional pipes!  I think that most slicers could actually handle that just fine (even though it's a non-manifold shape), but sculpting later could get funky.

With the basic form for my tentacles created, I went ahead and roughed out the rest of the pieces of my tentacular horror.  It's important to keep the geometry as simple as possible at this phase, because a lot of little tweaks and changes happen (all of these screenshots are from the final figure, which is why you don't see the positioning evolving throughout).  So, to that end, all of those tentacles are still Bezier curves that can be easily moved around to adjust their positioning.  The main eye is just a Sphere and I made the mouth/iris via a Boolean Difference modifier with an object that's hidden on another tab.  The teeth were originally generated with a curved array, but I applied that so that I could individually manipulate each one to get a more printable angle out of it.  All of that said, the geometry on this model is still highly malleable at this point, and I take advantage of that by slicing it and seeing if I need to move anything around to help it be more printable.

Once I was sure that I was happy with the pose, I moved on to sculpting.  So, I selected all of my model and hit shift-D to duplicate it, then pressed M to move them to another layer (which is how I make backups within a project).  With my backup made, I then selected all of the objects in my working space and hit Alt-C and selected Mesh to convert all of those objects into meshes (which also applies all modifiers).  There's one step you need to do for those tentacles - the Fill Caps option makes discs to cap the ends of the tentacles, but it doesn't actually attach them.  So, you need to Edit the tentacles (which are now a Mesh), select everything (with A), then press W and select Remove Doubles.  This will remove duplicate vertices, joining the caps to the ends of the tentacles.  From this point forward, it's significantly more difficult to make major modifications to the pose of the tentacles, because they're no longer defined by those nice Bezier curves.

That's ok though, because at this point I was happy with my pose!  So, all that was left was for me to go into Sculpt mode and add little details to the surfaces of the tentacles and the main body.  As you can see, I scribbled around a bit with the Inflate tool to obscure the perfectly regular taper undulations, then I used the Draw tool to make a veiny pattern along the tentacles.  What you can't see is that I used the Scrape tool to slightly flatten the undersides of the tentacles where I knew they'd need support (to make printing easier).  I also did a bunch of sculpting on the main eyeball/body to make it more disgustingly mouth-like.  All that said though, the sculpting is the less interesting part, because there wasn't much interesting technique that I can share there, just my usual trial-and-error approach ;)

And that's how I made my tentacles!  It's a fun process and I look forward to many more tentacular horrors in the future!

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