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Creating
Water Droplets on a Surface Using 3D Studio MAX and Adobe Photoshop
By
Kåre
Ola Jacobsson
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A
small tutorial on how to do water droplets on a surface
by using a Blend Material, some masking and other tricks
and flips to get a reasonable good looking surface scattered
with droplets
What
you need: 3DSMax 2.0/2.5/3.0, Photoshop 3.0-5.5, basic
understanding of 3DSMax's material editor, and of course
Photoshop, some spare time and a banjo. Maps used in
the tutorial: drop_mask.jpg, drop_mask.jpg, scratch.tga
Download:
drop_maps.zip
134 kB
1.
First start up Photoshop and CTRL+N to get a new document,
600*600 pixels will do (the bigger size the better though).
Paint some points with the pen tools in various sizes,
like the pic to the right. The pic will serve as both
bump and mask and you will save two different samples
each for its specific purpose.
Select all (CTRL+A) and do a gaussian blur to the whole
pic at about 0.8 strength, this is to smooth out the
jagged contour from the pen tool (of course you could
have used the paintbrush instead, up to you), now save
a copy name it drop_mask.jpg and place it somewhere
in your maps dir. Next select the magic wand tool and
select the black area, invert selection so you have
the white dots selected, again do a gaussian blur this
time at about 3.5 strength. This last blur was for the
bump map, so save a copy in your maps dir name it drop_bump.jpg.
And that's about it with Photoshop.
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| 2.
Time to start 3DSMax, or if it isn't already /Reset/Save
your current work in 3DSMax. Start with a sphere, fairly
"dense" 40 segments will suffice, create a target cam
with the target centered in the sphere. Put in some light,
create and position a target direct light pointing at
the sphere, make sure the hot spot covers the sphere.
Also create a box covering the works, including the cam
and the target direct light, apply a normal modifier to
the box (in the modify panel), flip the normals, by checking
the check box that says just that. The box will serve
as environment to reflect for the raytrace material you
apply to the drops later. Your perspective viewport should
look something like the pic to the right (the cam doesn't
show up clearly in the pic though, but it's there). The
effect of the flip Normals modifier is clearly visible. |
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3.
Now open the Material editor, the standard material has
to be replaced by a Blend material and you do so by clicking
the button that says Standard (lower right). The material/Map
Browser appears, choose the Blend material, discard old
material when asked. You should now have a gray Blend
material sample sphere in your no 1 sample slot and the
rollout for the material is as the pic below. Assign the
material to the Sphere in the scene. Give the material
a name such as Drop_Blend or something similar.
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| 4.
Both material 1 and 2 that is part of the Blend material
is of standard type, first let's deal with the material
1 that is to be the surface of the sphere ( material 2
will be the water drops). Click the material 1 sample
slot (where it says [Standard]), the rollout for the material
1 is just a standard material, for your amusement use
a bitmap for the diffuse, I choosed to use a crosshatch
type thingy (pic 1) to the left (all maps are downloadable
at top of page), also change the shading to metal, change
the Shininess and Shine strength to 50 each. Activate
your cam in the perspective viewport, render out a sample
at 320*240 pixels res, the rendered pic should be something
like the pic to the right (pic 2). Now to a important
thing, to be able to change the tiling of the maps individually,
i.e. bigger/smaller drops without changing the tiling
of the surface of the sphere, two mapping channels must
be used. Yes, I found this scary to when I first read
about it, but it's very useful and one really has to use
it in some cases such as this one. Choose the Sphere and
open the Modify panel, assign a UVW Map modifier to it,
in the rollout chose spherical and change the U and V
Tile to 2.0 each, render out a new sample, the "repeat"
of the texture is higher and the "scratches" seems smaller.
While you're at it assign another UVW Map modifier, spherical,
this for controlling the tiling of the drop maps. At the
rollout change to UVW map to Channel 2 for this modifier
like the pic 3, leave the tiling for now, adjust those
later. |
pic
1
pic
2
pic
3
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| 5.
Open the Material editor again, click the Material 2 sample
slot, a standard material rollout appears, change from
standard to raytrace material type by clicking the Standard
button, discard old material when prompted, the raytrace
material rollout is slightly different from the standard
material (pic 1), as seen to the right. Now click the
bump slot where it says None, and choose bitmap from the
browser, find the drop_bump.jpg you painted in Photoshop.
Important in this rollout is to change the texture mapping
to address the 2nd UVW Map modifier in the modifier stack
for the sphere, so drop down the menu and choose Explicit
UVW 2 instead (pic 2). Go to the "root" of the raytrace
material. Some changes to the basic raytrace material
has to be done, first check the 2-sided checkbox, to have
the material transparent click the black box next to the
Transparency and bring the "sliders" down to R:235, G:235,
B: 235, take up the Shininess to about 70 and the Shininess
Strength to about 150 (pic 1). Finally open the Raytracer
Controls rollout and enable the two check boxes (pic 3).
Do a test, render out the cam viewport again, no drops?
Things aren't quite done yet, masking out the drops has
to be done, so get to the root of the Drop_Blend material.
pic
3
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pic
1
pic 2
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6.
Click the Mask button (pic 1) and choose a mask map, two
sample slots available for the mask, a map and a
mask, click the map button, browse from new, and choose
a bitmap Map locate the scratch.tga in your maps dir once
more. Second click the mask button, browse new, choose
bitmap Map, find the drop_mask.jpg and you're almost done,
when you have assigned the drop_mask.jpg there is one
important thing to do, change the Mapping to Explicit
UVW 2 (pic 2). In the Material/Map Navigator your material
tree should look like the one below (pic 3). Render out
the cam viewport, the drops are there, but they are a
bit to big a sized, so choose the sphere and in the modify
tab choose the topmost UVW Map modifier and change the
tiling to U:3, V:2, render again. The output from the
render this time will look something like the picture
below (pic 4)
pic
4
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pic
1
pic
2
pic
3
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7.
Ok time to set up the environment, so the raytrace material
has something to reflect. Put in a omni light between
the sphere and cam and in the rollout exclude the sphere
from being lit by the omni (pic 1).
To
see the effect of the raytrace material, open the material
editor again and click the almost black color box next
to the Reflect, drag the slider down so you get a gray
(R;G;B=126) value instead, render again. The lit box
clearly is reflected in the droplets, a bit to much
perhaps, so bring the sliders down to R;G;B=40. Render
again, there seems to be a problem with the color of
the drops, to white in the not directly lit areas and
to black where lit, you can control this by doing the
following. Open the Mask channel again, click the Map
button so the Bitmap parameters appears for the scratch.tga
bitmap, now click the button which says Type: Bitmap
then when at the Material/Map Browser, browse from new,
choose the Output Map, when asked replace Map,
check the Keep old map as sub-map? and click OK. You
now have control over the output from the map channel.
Drag the Output amount spinner down to about 0.5-0.6
(pic 3).
And
that's about it for this material, your material tree
should look like pic 4. If you render out a sample now
you should have something like the picture below (pic
5), the scratch map shows trough the drops more clearly
now, you can go back to the material editor and try
out other settings with the specular/reflect/IOR/opacity
settings to fine tune the material/drops. You could
also try some experiments with lights set up, for example
have a spot to control the hi lights of the droplets
etc. etc.
Animate the drops, perhaps a new "grayscale" drop map
has to be made, a more stretched out drop shape would
do better when animated.
pic
5
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pic 1
pic
2
pic 3
pic
4
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"The
Space People think factories are musical instruments.
They sing along
with them. Each song lasts from 8 a.m. to 5 p.m.
No music on weekends"
Talking
Heads
Please
adjust your monitors brightness/contrast, you should see the
letters C D E but not A and B
Handmade
by Kåre Ola Jacobsson, no animals harmed during the
process.
Copyright
© 1999 Kåre Ola Jacobsson
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