Getting Perfect Rotation From knobs

I’ve been using Infini-D by Metacreations (now corel) to build a 3d model of the knob. I suppose any 3d rendering application will work fine. This seems to be the easiest way to get perfect rotation out of knob actions. Photoshop’s rotation feature just doesn’t quite cut it. Rotated images usually end up wobbly. I think the vectoring actions in the upcoming Photoshop 6 will probably work, but we shall see.

With the 3d Modeling application, you create a model of the knob, then animate it to rotate around a center axis. After rending the animation, you can cut and paste each frame into a film strip and save the assembled animation frames as a jpg and pack it into your mod.

Dancing Pixels on the Knob Background

Yep this happens if the background isn’t exactly the same in each frame. A quick way to create a perfect set of background frames is to select a single frame with the selection tool in photoshop, then “Define Pattern.” Then select the entire strip and “Fill” using “Pattern.” Move this background layer behind the knob layer and you have a perfect set of backgrounds for each frame.

How ReBirth Handles Knob Animation Strips

After experimenting for such a long time, I’ve figured out how ReBirth responds to these animation strips. The program reads the horizontal width of the jpg - Total w(pix). It then divides that number by the amount of frames it’s supposed to have - Frames. It then subracts 1 pixel for the divider line - div(pix). This determines the animation frame width - w(pix). The height is calculated by reading the vertical size of the jpg - h(pix)

Altering the vertical size of knobs is pretty easy, just increase the vertical size of your image. Increasing the width of the knob frames requires a bit of algebra. For example, I usually like to make the 909 knobs the same size as the 808 knobs. The 909 knobs are displayed in 12×12 pixel frames. Increase them to 13×13 pixels as follows:

h(pix) 13
w(pix) 13 + div(pix) 1 = 14pix
14pix * 41 frames = 574 pixels
574 pix - 1 div(pix) = 573 pixels.

so the final image size of 12565.jpg (the 909 knobs) would be 13 pixels high by 573 pixels wide.

Short Cuts

I use the Avid Quicktime Import Plug In (which came with the Avid Video editing software for the Powermac 8500) - this can be a wee bit difficult to find now that the software is so outdated.

Since the movie is imported as a vertical film strip, it must be rotated 90¡ counter-dclockwise. To compensate for this rotation the animation start position is usually about 10 o’clock Mid position is 3 o’clock and finish position is usually 8 o’clock. When rotated. the start position will be 7 o’clock, mid position 12 o’clock and finish position is 5 o’clock.

Reduce the image size to fit the dimensions listed below with the Bicubic dither setting. I only reduce the image width and let photoshop automatically calculate the height (proportions constrained).

On the new layer, copy the background of knob (including fixed shading etc onto this masking layer. Then disable the bottom knob layer so that only the mask shows (the transparent grey and white blocks should be visible where the knob normally is).

Select the area of 1 frame including divider (e.g. 12507.jpg select 30 h x 31w area) Then “Define Pattern” from the selection Create a new layer. Select ALL . Then Fill with the pattern. If your dimensions are set properly, the Fill should align perfectly with each frame of the knob allowing the changing steps of the knob to show through and keeping the frame background identical on each step:)

Save this image as a photoshop document keeping the layers in case you need to make changes. Then save a copy as a jpeg into your MOD folder RePeat this for each knob Well this is how i do it…Perhaps you can use some of the techniques involved.. hope this helps a bit:)
 

Image	h(pix)	w(pix)	div(pix)	Frames	Total w (pix)
12507.jpg	30	30	1	54	1674
12521.jpg	13	13	1	36	504
12522.jpg	13	13	1	36	504
12552.jpg	19	18	1	32	608
12565.jpg	12	12	1(except 41)	41	532 (533-1)

You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.