UV mapping a sphere

Torch

Hi all, I've been trying to get my head around UV mapping a sphere (excuse the pun), I've checked the Polycount Wiki and tried a few of the methods but I seem to keep getting a lot of distortion no matter what method I use. Does anyone have a set way or prefered method of doing it? I want to get a grid like pattern over the sphere like netting, so I want to have the UV's pretty straight with as little distortion as possible. Any advice appreciated, thanks

Mark Dygert

Have you tried using a Quadsphere?

http://www.polycount.com/forum/showpost.php?p=1312335&postcount=16

SnakeDoctor

Here is what worked for my planet. Scroll down to Joshua Stubbles post explaining the workflow. My results are below his. Quadsphere is really good if you plan on polypainting it, but I found it to be a pain when trying to work with Photoshop.


http://www.polycount.com/forum/showthread.php?t=85429

Torch

Hey guys, thanks for the quick reply I've tried the Quadsphere but the results came out kinda wonky, the UV's weren't perfectly straight so the 'netting' normal map was a little skewed. I'll try it again tonight, maybe I did something wrong and overlooked it. Will also try the method mentioned by SnakeDoctor, thanks a bunch

Mark Dygert

It can help to unwrap the cube before rounding it out, if you unwrap it afterward it will relax oddly, accurelty, but oddly. If you're using 2012 you can use the "Straighten Selection" to square off the UV shells.

JoshexDirad

Torch said:

Hi all, I've been trying to get my head around UV mapping a sphere (excuse the pun), I've checked the Polycount Wiki and tried a few of the methods but I seem to keep getting a lot of distortion no matter what method I use. Does anyone have a set way or prefered method of doing it? I want to get a grid like pattern over the sphere like netting, so I want to have the UV's pretty straight with as little distortion as possible. Any advice appreciated, thanks

https://polycount.com/discussion/comment/2794716/#Comment_2794716

here, I just figured out a good way to do it. this thread shows several ways to do it, but, the last way I just did it, is superior to every other way I've tried. I also explained WHY spheres are such trouble and WHY they have to be done a certain way to work. I also supplied 2 texture sets to illustrate the reasoning behind how and why to avoid seams and creases.

for a summary:
First I must define Seams and Creases.

Seam(s): to refer to a place on a surface where 2 materials or textures meet; in which the pattern of the pixels is broken causing a visible line.

Crease(s): to refer to a place where CONFLICTING Texture Normals AND, either Image bounds OR UV outline edges between 2 UV Islands Meet causing a 3D Per-pixel ridge.

Seams are easy to deal with, you just make sure the texture repeats in all 4 directions or on all edges of the UV outline.

Creases are kinda a pain to deal with as you need to force your baking engine to contemplate BOTH sides of the sphere at the same time so that it generates the Normal Colors at the edges to be contiguous.

Klunk

you can use render to texture across mapping channels to remove seams regardless of the base mapping used. It's a pain to do and can result in ultra distorted textures but it's an option