Project 3 - Ice

In class we worked on developing ice forming on an object, similar to the reference in the following pictures from ice storms.

I started experimenting with the Renderman Blobbies, with subsurface scattering. I have one image of the frog model I have been using with blobbies on top.

Next I have some Houdini tests with particles traveling down a surface, shaded with an ice shader within houdini. I did however spend a lot of time exporting point information from Houdini, as well as just the mesh verts, but ultimately I did not use them to generate Renderman Blobbies, as I thought this would be reinventing the wheel.

Here is a sample of the plain point information exported from Houdini in RibArchives.

AttributeBegin    # {
    # /obj/geo1
    Sides 2
    Points    # {
    "P" [-1.25006473064 4.08561372757 1.81133916755e-08 -1.24825227261 4.05188751221 ...

The line with the point information is put all onto one line, which is vitually uneditable within cutter for manipulation.
Here is an edited version with the help of python, with a desireable result.

-1.25006473064    4.08561372757    1.81133916755e-08
-1.24825227261    4.05188751221    -0.0147266974673
-1.25006473064    4.08561372757    1.81133916755e-08
-1.25006473064    4.08561372757    1.81133916755e-08
-1.25006473064    4.08561372757    1.81133916755e-08
-1.24579274654    4.03273105621    0.00331232789904
-1.24783432484    4.05266094208    0.0371947772801
-1.24989557266    4.07498502731    0.000266458489932
-1.38564825058    3.45399403572    0.180842906237
-0.664704442024    3.12492132187    -0.132541209459
-1.46634733677    3.36782002449    0.33711129427
-1.60098993778    2.7633626461    -0.303473204374
-1.27764320374    3.50596952438    -0.125497311354
-1.08262515068    2.95252251625    0.0298104919493
-1.20153391361    3.13188052177    0.334737479687
-1.12168884277    3.33281540871    0.00239798007533
-1.25006473064    4.08561372757    1.81133916755e-08

The python code stripped the beginning information, and searched for blank spaces, creating new lines for every third iteration.

#specify range
for j in range(1, 21):
  
#specify path with new and old names, concatting and padding
    f = open("/stuhome/vsfx419/archives/pointsHou_%04d.rib" % (j), "r")
    g = open("/stuhome/vsfx419/archives/points_%04d.rib" % (j), "w")
    
  
    
    lines = f.readlines()
    line = lines[4]
    line.strip('[')
  
#take off beginning prefixes and suffixes
    
    numbers = line.split()
    numbers.pop(0)
    temp = numbers[0].split ('[')
    numbers[0]=temp[1]
    temp = numbers[len(numbers)-1].split(']')
    numbers[len(numbers)-1] = temp[0]
    
#iterations for writing out the file with returns
    for i in range(len(numbers)/3):
    
        g.write (numbers[i*3])
        g.write ("\t")
        g.write (numbers[i*3+1])
        g.write ("\t")
        g.write (numbers[i*3+2])
        g.write ("\n")
    g.close()
    f.close()
    
#progress report
    print "file %04d.rib complete!" % (j)

Here are my particles in Houdini

This was my final result, completely done in Houdini.

Please click for higher res

I solved this with Houdini's particle systems and metaballs. Although my effect is not perfect, the setup I have with a follow particle is great for forming the ice in a specific direction, similar to the reference images. Just move the follow particle, and the splitting particles will follow it and appear to form in that direction.