How to create icicles hanging off an object?

Question

Is there a way to create icicles, for example like this:

I was thinking if there was some way to use a Snake Hook brush on many random places at once with different strengths etc., but I don't know if this is possible.

How can I achieve this?

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Image from Wikipedia

Answer 1

Icicle Generator

This addon creates rows of very realistic icicles along all selected edges of an object. You can download and read about it here.

Here is an example of how beautifully they render:

To enable Icicle Generator:

1. Download the addon by clicking here.

2. Open the User Preferences:
   Info header → File → User Preferences

   

3. Click on Addons at the top of the Preferences window, and then click on the Install from File button at the bottom of the window:

   

4. Next:

   • Find the addon file and select it (the file can be a .zip file -- you don't have to unzip it first)

   • Click the Install from File button

   • Then enable it by clicking the checkbox on the far right of the addon

   • If you want Icicle Generator to be enabled by default in the future, click on the Save User Settings button:

   

5. To add icicles to an object, the object must be a mesh. If it is a curve object, simply convert it to a mesh object with ALTC → Convert to Mesh

6. Go into Edit mode, select all edges you'd like to have icicles hanging from, make a copy of those edges and make them a separate object:
   SHIFTD → ENTER → P → Separate Selection

   

   This will create a new mesh object composed only of the edges where you want icicles to be. NOTE: Don't move this icicle edge object -- it's in just the correct place now.

7. You MUST apply the icicle edge object's Location, Rotation and Scale while in Object mode before adding the icicles:
   Object mode → select object → CTRLA → Location → CTRLA → Rotation & Scale

8. Now select the newly created edge object, go into Edit mode, select all, and add the icicles:
   Select edge object → TAB → select All (A) → SHIFTA → Icicle

   

9. To adjust the settings, open the Tools panel (T):

   

   These settings (above) yield icicles like this:

   

   However, if you want a more random appearance, set the Min D to 0.2 and Min R to 0.01 -- this causes some icicles to be so small they appear to not be there, yielding icicles like this:

   

   NOTE: You MUST set all the settings the way you want them to be before you do ANYTHING else, otherwise they cannot be changed again.

10. Now rename the newly created icicles object to "Icicles" and assign them a Glass material:

    

11. If you want to, you can give the icicles a bump texture.

Answer 2

You could use a Particle System of type Hair.

Make a plane and apply a particle system to it.

Also make an icicle as a separate object, or make several and make a group out of them. Remember to set the origin of each icicle to where it should start growing on the plain, and also CtrlA apply rotation&scale.

In the particle system properties, go to Render. If you made just one icicle, choose the Object tab and your icicle as Dupli Object. If you made several, go to Group tab and choose your group.

Then play with settings in particle system to get correct rotations, placements and scale. Randomness can be applied to all.

Here's a quick result with only one icicle object (open image in new tab to see full size):

Edit:

If you want to fine-tune location of icicles, set Particles/Face = 1 and edit the faces on the plane to exactly where each icicle should originate. Remember to set matching count to amount of faces.