#Transparent Clouds Map?
14 messages in this thread
I'd welcome some tips on how to create a "transparent" clouds material.
I have a spherical object whose material is a nice GIF map of the earth's
surface (I think I downloaded it here some months ago: BIGWLD.GIF a 330k file
containing composite satellite pictures of the earth's surface).
I've created a slightly larger sphere to surround the globe object. Its surface
material is a map of cloud formations as seen from space. (I think I downloaded
that file from here as well: EARTHC.GIF). This cloud graphic contains a lot of
white swirls on a black background.
I'm trying to make the black parts of this map completely transparent so only
the white cloud sections appear to "cover" the globe object. I've experimented
in the Materials Editor with various transparency and opacity settings, but I
still find that the black sections still significantly darken the underlying
globe surface. I've even experimented a little with some RGB masking in Video
Post but without much apparent success.
I'd welcome some tips from more experienced users who have worked with
something like this.
Thanks,
Lee
lee-
are you using the clouds image as a texture map or as a transparency map?
you want to be using the latter ( If you are already doing this then ignore me)
in which case it should work fine providing the slider for the transparency map
is set to 100%
Also – light sources using shadow mapping DON'T see thru transparency maps so
use raytraced shadows instead.
hope this helps
Stuart
Stuart,
Thanks for the very helpful tips. I believe I've correctly implemented your
suggestions. They've certainly helped. I wonder, however, exactly what you
mean by a "transparency map?" Are you talking about an opacity map? A material
with its materials editor transparency slider positioned all the way at 100% or
what?
Thanks again,
Lee
>> I've experimented in the Materials Editor with various transparency and
opacity settings, but I still find that the black sections still significantly
darken the underlying globe surface<<
Lee,
Assign your cloud map to the Opacity and Texture 1 slots of the Materias
Editor. Set the Opacity slider to 100%, which means 100% transparency ( dark
colors hide, light ones stay). Also of great importance is to set the
attributes of the object ( setting in the 3D Editor) you are assigning the map,
not to cast shadows, or the shadow of the object (not the mapped image) will be
cast. Often times to get more of a contrast for things like clouds, I like to
create an alpha map ( a grey scale image of the cloud map) to put in the
Opacity slot. This ensures the detail of the clouds will not be lost.
I just spent about a week just creating transparency maps using Kai's Power
Tools and Photoshop for a video. The results were well worth the exploration.
Hope this helps!
Bill – Triffet Animation Co.
Bill,
Your comments helped a lot. Many thanks!
Gratefully,
Lee
Hi Lee,
I've used that cloud technique a few times, almost exactly as you are. I
expect you've already put the cloud map in as an opacity map, but you don't
want to use it as a texture map because the clouds will start to darken where
the map fades to black (where the cloud "edge" fades), just define the color of
your clouds with the material's standard surface color definition.
And, the best thing about this technique is that Raytraced Shadows _will_
calculate the opacity values properly and give you shadows cast on the planet
_only_ below where the clouds are. (One of my favorite "simple" planet
effects.) In that case you want to leave the object's shadow casting attribute
ON. Note: you _will_ take a significant hit in rendering time when doing this.
Enjoy,
– Ron
Ron,
Your explanation really helped. Thanks!
Gratefully,
Lee
Hi Lee,
I needed transparent clouds for a tv-movie, I've made for my tv-station
(Germany). I spent some nights on the "transparent" problem. Now I've found a
good solution: I create a black/white-mask from the map-picture (for example
with Picture Publisher: Very easy to mask the transparent areas!) and then, I
put together the original map and the mask map in the material-editor (origial
map: Texture1, Opacity: Mask-picture). Now you can reduce also the transparency
of the clouds.
I hope, you unterstand my "virtual English"!
Bye
Stefan
Stefan,
Thanks for your very clear, sensible explanation of how you created a
transparent cloud map. It's quite helpful. (Your virtual English seems
virtually perfect to me.)
Gratefully,
Lee
Having just read the previouse discussion, I would like to follow up. I've
recently noticed some animated globes with animated swirling and morphing cloud
maps. I'm wondering if anyone out there has worked on this, and do you have any
suggestions for creating such a map/flic.
Andrew,
I'm in basically the same position you are–a beginner with this type of 3DS
rendering. Your best bet is from others here who have already replied with
helpful suggestions.
As I understand it, the basic challenge is to edit your materials (clouds map)
for desired transparency, to use ray-tracing in your shadows, and (optionally)
to consider using a mask over the cloudless areas.
Good luck,
Lee
Thanks for getting back. I probably should have posete the message
differently.
Hi Lee,
One solution I found was to use the mask slot in the materials editor
using the clouds map and then set the negative flag in the mask
Simple solution if your non cloud part of the image is all black.
-john-
John,
Sounds like a valuable piece of advice. Although I've now rendered the project
which first prompted my inquiry, I've filed your tip for future reference.
Thanks!
Gratefully,
Lee