This is not really a tutorial. Just a trick
to make it the right way.
Mapping objects to sphere in Filters>Map>Map Object yields rather horrible results as the image you are
mapping appears
to be stretched along parallels of the
sphere.
How
to diminish the distortion and get more or less right proportions?
To get my point clearer I'm attaching these 2 images, one with strong distortion and the other with more or less correct proportions.
![Image](http://gimpchat.com/files/2204_Face-normal.jpg)
(The original image from
DA)
![Image](http://gimpchat.com/files/2204_3d_reference___face_loops_by_Athey.jpg)
Both images were created in Map Object with identical settings from the same size image with face
The only difference is how you 'prepare' the image
to be mapped.
I've found empirically that
objects to be mapped should be 'squeezed' from sides by the factor of 1.5 (may not work for any object
but in most cases it does)
How we do it?
Let's say, you want a
sphere with mapped object
to be around 700 x 700 pixels in size.
Bear in mind that
mapping objects to sphere will produce a
sphere which is half the size of your original image.
Therefore, our image should be about 1400 x 1400 pixels before
mapping.
I used Hexacol BW pattern for better visualization. Here are the results.
The image on the right was made from 1440 x 1440 square without prior 'treatment'
![Image](http://gimpchat.com/files/2204_normal.jpg)
To get the left image I created an image with 1440 px Height and 1440*1.5 Width. We get 2160 x 1440 pixel image
(yes, unlike 2.6 in GIMP 2.8 you can enter common mathematical operations [+ * / -] for height and width) and then filled it
with Hexacol BW pattern.
![Image](http://gimpchat.com/files/2204_Image%20001.jpg)
Scale the image
to the desired 1440 x 1440 square as shown at the picture below.
Don't forget
to unchain before you enter the width and use Lanczos interpolation
![Image](http://gimpchat.com/files/2204_Image%20002.jpg)
Our pattern becomes 'sqeezed' from the sides.
Here's our face after such a treatment
![Image](http://gimpchat.com/files/2204_Face-sqeezed.jpg)
Now you can map it
to sphere to get less distorted results.
Thanks for reading.
P.S. Bonus animation for those who had enough patience
to read the whole post
![Image](http://gimpchat.com/files/2204_RotatingSphere.gif)