There are two ways. One is simple, the other more complicated. The simpler way, the way which, IMO, produces the best results, is to extract an existing [V] ani from the sparky.vp, find a ship that fairly closely matches the shape of your ship. Then extract the ani with aniview, replace the first image with a top down, high contrast image of your ship (remembering, of course, to reapply the existing pallette before saving in pcx) and recompile the ani with Anibuild. You may need to fiddle with the positions of the various elements, insert a few pixel rows here, remove them there, or, in some cases, completely flip or rotate the shield ani to fit the shape of your ship. But overall, 90% of the time, this method will produce a quick shield ani that looks just as good as the [V] ones.
On occasion though, you'll get an odd shape which requires a brand new shield ani be made. The easiest way I've found to do this is thus:
1. First, take a top down picture of your ship in PCS2 or modelview and paste it into your image editing program (I use PSP 9). Resize the ship to somewhere around two or three times bigger than it will appear on the icon (The enttire shield icon image is 112 pixels wide, 93 pixels tall. A wingless ship like an apollo or herc will normally be around 40 pixels wide and 65 pixels tall)
2. Next, create a new layer and draw a rough, curvy outline of the ship with the ellipse tool, filled in white, ideally with antialias on. Leave space between this and the edge of the hull, as the edge of this shape will be the outer edge of your shield ani.
3. Now, select the white outline you've created and use the selection contract tool to decrease the selection a few pixels, between 5 and 10 should be enough. Then invert the selection, and use the feather selection command to expand it again, another 10 or 15 pixels.
4. Invert the selection again and fill with black. You should now have your ship in the middle of a white halo that looks something like the [V] shield.
5. Resize to the appropriate scale (resizing will cover a multitude of sins, but fiddle the settings to get the best quality resize - there are a bunch of different ways PSP can do the resize maths, and some look better than others).
6. Now, draw 4 lines in black (3 pixels with anti aliasing tends to be about right for the width) to separate the four shield quadrants.
7. Now, separate the 4 shield arcs into 4 different pictures, all the same size as the icon you just created (i.er. 112x93), leaving the (high contrast, greyscale) image of your ship alone in the centre of a now blank black field.
8. The second last step is load the correct HUD Palette (which can be taken from any hud element when saved by aniview to pcx files) onto all five images.
9. Finally, you may need to clean up the antialiasing manually on the outer edge of your shield. Sometimes you can generate decent anialiasing, sometimes you don't. (See the attached picture, second row. The left hand version generated decent antialiasing, but had no internal fade-out gradient. The right hand image had an internal fade off, but all the external antialising is manual, hence the messy left shield bracket).
It's important to play around with these steps to get the best results, but basically all you need to be able to do is expland, contract and feather selections cleverly. Once you've got those tools mastered, they're relatively quick and easy to do.
The attached image are a couple of Shield anis I've done, with the top row using the simple extract and replace method, while the bottom two are two attempts using variants of the method I outlined above.
[attachment stolen by Slimey Goober]
