PDA

View Full Version : Wrapping polygons over a sphere



dranos
03-19-2004, 08:31 PM
I'm trying to create a wireframe type globe and I'm completely lost. I dont know where to start. If I create the continents in 2D then import them into lightwave, how do I wrap them unto a sphere? I'm having the same problems with the longtitude and latitude lines. Any suggestions?

Tony3d
03-22-2004, 09:44 AM
There is a plug-in on flay.com called wrap sphere that should do it and it's free!

dranos
03-22-2004, 10:21 AM
Thanks but it seems the plugin is no longer available. Is there any other source I can get it from?

NigelH
03-22-2004, 10:56 AM
Do the surface features have to be polygonal? Why not just wrap a texture map of the earth onto a sphere and achieve the grid effect via transparency/clip maps?

dranos
03-22-2004, 11:50 AM
The continents, longitude and latitude lines have to be 3D. Client wants it to appear to be an award type sculpture.

NigelH
03-22-2004, 12:03 PM
Then I would build the objects flat (well, with as much depth as you need) in Modeler with a 2:1 width to height ratio just like you would create a texture map destined to fit on a sphere. Then, in Layout, apply bend deformations to the flat 'map' object 180degrees along the height (longitude) and 360degees around the circumference (latitude).

But that's just me. :)

dranos
03-22-2004, 01:04 PM
Could you give some more details on this tool. I checked my object properties and added the bend deformation but I don't see the options to do what you suggested.

NigelH
03-22-2004, 02:11 PM
OK, my goof, the def tools in Layout don't work quite the way I expected when layered on top of each other. Better to perform your deformations in Modeler (probably as a morph target). Where the tools have better control.

Beamtracer
03-22-2004, 02:36 PM
Using an image map is the way to go, rather than polygons. There's B&W image maps out there on the web, ready to use. You don't want to model these sort of things!

dranos
03-22-2004, 06:06 PM
Thanks guys. I found a free globe on 3dcafe.com that will pass after a few mods. Its a shame lightwave doesn't do this kind of thing easily. I remember doing this stuff with the click of a button in Cinema 4D. I wont go back though.

KPS
03-23-2004, 07:09 AM
Here is one I've done using bumpmaps.
:)

dranos
03-23-2004, 08:20 AM
Thats really nice but I really wanted the deep blue ocean spaces to be empty spaces. I found this at 3dcafe. If only it had the longitude & latitude lines.

KPS
03-23-2004, 08:32 AM
How about if you create a nother sphere of the same size, then make a transparency map for the lines. that might work!
You can also create different sized rings and rotate and place them into place were you want the lines??

NigelH
03-23-2004, 08:35 AM
Longitutde and latitude lines are easy (especially longitude).

For longitutde, just create a torus (ring) primitive with the correct circumference for the globe and the thickness you want the lines to be. Turn it on its edge, then clone it around the Y axis for each line of longitude.

For Latitude, you can use the same torus for the equater, but create rings with smaller circumferences (but the same thickness) for each ring towards the poles.

That's the basic idea, anyway. For the actual math, you're on your own. :)

dranos
03-23-2004, 08:47 AM
I know this globe is easy to get to the stage I want it. The problem is that I would have prefered to know how to model continents like that for similar projects in the future. I'm sure whoever modeled this globe used a simple operation. Thanks for the help.

munky
03-24-2004, 06:19 AM
hello there
If you have a compositing package like Combustion/ after fx/ digital fusion then an easy way to get lat and longditude lines is to make a sphere the same size or just a tad bigger than your globe. give it the amount of sides and segments that you want for your lat and long lines. Surface it black, parent it to your globe and in the object properties pane go to EDGES and check silhouette edges and sharp creases make the edge colour white Turn off all your other objects and you will get a nice hidden line globe wireframe which you can then key onto your globe.

regards

paul

dranos
03-24-2004, 06:30 AM
I'll try that and see if the client will buy it.
Thanks