Spherical Map Tiling

[gregtee]

Is this possible?  I don't see any parameters for this in the Image Map Shader.  Seems it's not possible to wrap a latlong image around a planet more than once. 

Thanks

Greg

[bigben]

Is this possible?  I don't see any parameters for this in the Image Map Shader.  Seems it's not possible to wrap a latlong image around a planet more than once. 

Use the image size in conjunction with the repeat x and/or repeat y. Number of tiles will be 1/ImageSize

[gregtee]

Thanks.  I've tried this and it seems to be pinching at the poles.  BTW, I should mention that I'm doing this to a planet, not a simple sphere object.  I'm trying to take a moon crater map off the NASA site and have it tile more around the planet to increase the number of craters on it with the goal of making the moon look bigger.  This approach seems to cause pinching at the poles, unless I'm going something wrong.

Thanks again

greg

[AP]

I think you need two things here. One is image synthesis and second, spherical map conversion after synthesis patching of images making a seamless map. I think in this case it all needs to be done with one or two external applications. Something like a photography software that stitches images together into a 360 by 360 degree spherical panoramic map. There are some panorama creation software's out there that do this but for this life of me I can not recall which ones off the top of my mind.

[AP]

Alright, I found some programs that could work.

http://www.serif.com/free-panoramic-photo-stitching-software/

http://hugin.sourceforge.net/

http://www.ptgui.com/

http://www.photostitcher.com/

http://research.microsoft.com/en-us/um/redmond/groups/ivm/ICE/

http://www.arcsoft.com/panorama-maker/

http://www.gigapan.com/cms/shop/software/gigapan-stitch-efx

http://www.panavue.com/

http://www.kolor.com/download-autopano-panotour-panorama-virtual-tour-software.html

http://www.easypano.com/download-panorama-software.html

http://www.pixtra.com/

[bigben]

As Chris mentioned you need to create a different image. The spherical image map has a particular distortion to fit back onto a sphere. You'll also find in your tiled image map that there are horizontal lines because the top and bottom of the image map is a single colour.

One thing you'll find with craters though, is that it's very hard to judge the size of a planet (and thereby perceive how far away you are from it) by looking at the size of craters.  The moon is like a crater fractal. No matter how close you go there are always "big" craters and "little" craters.

Maybe try Callisto?  It has lots of craters and looks (is) bigger than our moon.

[Dune]

Can't you use procedural craters?

[bigben]

Alternatively, load the image into photoshop, duplicate the layer, rotate it 180°, offset it, set the blend mode to screen and adjust the contrast.
Or apply a pnao transformation to it and blend (2nd image is rotation 90°, pitch 90°).

[gregtee]

All great suggestions guys.  With regards to Dunes procedural craters I'd be willing to give that a shot if there was a way to populate the planet with enough of them to make it realistic.  I'd need thousands of them I'd imagine to really pull off the look.  I seem to recall the crater shader is a single instance approach.  It would take a considerable amount of time, not to mention a very large tgd script, to manaully place all those craters?

Thanks everyone.

Greg

[Dune]

You can make procedural circles with a blue node setup, and use color adjusts and merge shaders to make rings and craters. A few sizes mixed, and you quickly got a moon filled. There's a few threads about procedural craters, so tgd's or tgc's to be found. One thread is here: http://www.planetside.co.uk/forums/index.php/topic,7327.0.html

[AP]

Also, there is something I did a while back but as to the effectiveness of it, who knows.

http://www.planetside.co.uk/forums/index.php/topic,4484.30.html

[TheBadger]

Greg,

Can we see an image of the new moon when its done (or close to done) Just sounds interesting.

[fleetwood]

Since Terragen now allows us to directly select the voronoi noise type you can get a type of global crater pattern using an ordinary power fractal.
If you make all the scales of the fractal the same or nearly the same, for example 500 500 500
and set the noise to voronoi billows you will get circular patterns.

String a few PFs of different size voronoi billows together and adjust the color offsets toward black to reduce
the number of craters or toward white to have more. Displace or blend by whatever method you prefer into the terrain.
I'm sure something much more sophisticated can be done but here is a quick example of what I mean.

ChrisC : I just now saw you used voronoi billows as the basis for your crater method also.

[AP]

Correct but having nice looking crater rims is difficult and the rims need some scattered debris spreading outward.