Archive for November 30th, 2011

Photoshop and Perspective part II: Creating reusable tools.

First of all, belated happy Thanksgiving to all who celebrated it last week.  I’m back now, and ready to pick up where we left off.

Not fully satisfied with the lengths I took previously in exploring the possibilities of perspective tools in Photoshop, I decided to create some more that hopefully have broader application.

For example, what about 4-point unlimited perspective?  Creating scenes with wide angles is immensely useful for fitting in a large amount of information in a confined space.  In addition, unlike drawing with two-point or 3-point perspective, there is no fussing about where to put the vanishing points (maintaining a believable perspective with those techniques as one moves and adjusts the vanishing points is more difficult as the distance between them changes non-linearly.  4-point perspective maintains  the same distance between VP’s by curving perspective lines).

Doing this exercise once and well, provides a digital artist with a reusable tool that can be dragged, dropped and scaled into frame ready for composition.

We’re going to be operating in Photoshop again, so bring up a window and create a new, high resolution file and guide layout similar to what you see here:

The horizontal and vertical guides should cut across and down the middle and bisect the workspace.  The horizontal line is your horizon, so draw a line across it using whatever method you prefer, as long as its straight.

Now, create a new layer and using the shape tool, make a perfectly circular path that touches the four edges.  Turning on the grid helps here.  Make sure the output is set to paths (not shape layers or fill pixels) in the options bar.  Briefly switch out to your brush tool and check the size of the brush as it’s the one that we’ll be stroking the paths with.  If it’s satisfactory, switch to the direct selection tool, select the path, right click on it and select ‘stroke path’ followed by making sure the brush tool is selected from the drop down menu in the pop-up.  Now the screen looks like this:

Before going on, let’s rename the path to something more specific than “work path”.  Doing this is also just good  practice as the work path gets overwritten each time a new path is made and we’ll be wanting to reuse this circle over and over again as we will see shortly.

Now, let’s move the circle precisely by selecting the path using Edit: Free Transform Path tool, and clicking the Use Relative Positioning option  represented by the small triangle icon in the options bar, zeroing out the x and y position values.  Pick a value for changing the vertical (Y) position and enter it into the Y position in the options bar.  Remember, this gap you are creating between the circle you just traced and the current one you are about to will be the constant unit of distance/depth in the resulting perspective template represented by all future circles, so keep this in mind.  I’m using -375 pixels in this case (though yours may vary) because I’m going to concentrate on creating the graph on the lower half of the image and then mirroring it upwards after I’m done.  If you want to approach it the other way from the top down, that’s fine, just enter your displacing values as positive numbers rather than negative.

Before proceeding, check to make sure that you’ve fixed the aspect ratio option (chain icon) in the options bar, and while clicking and dragging over the W: or H: scale entry, dynamically scale the circle path so it again passes through the points where the horizon and side image boundaries meet.  Like this:

After confirming the transformation, go back to the direct selection tool, right click on the path and stroke it again as before.

Keep repeating this process until the number of desired units measured towards the horizon is reached.  I’ll show eight iterations here for illustration:

Now this produces a bunch of pixels outside of the image plane that both take up extra space, and will hamper our attempts to mirror these lines up to the top half, so using a box selection, take everything below the horizon (snaps-on helps) and create a layer mask for the layer we’ve just put all these lovely lines on, then right click on the layer mask in the layer palette, and hit apply layer mask.  This should get rid of all the excess information we don’t need.
Duplicating the layer, mirroring the part below the horizon to the part above yields:

Not too far to go now.  Merge the two curve layers together and duplicate that layer, and follow that by enlarging the canvas size horizontally by 150%.  Move the newly duplicated layer so that the left vanishing point is now directly over the center of the original circle (where the guides meet) and create a new guide marking the center of the circle in the duplicate layer just shifted.

Repeat the process again, expanding the horizontal canvas size, this time by 133.3333% and duplicating  another circle layer.  Move it the same as before with the vanishing point of the new circle aligning with the center of the previous.
Now you have vanishing points for all directions, North, South, East, and West, with the sides of the canvas and the VP’s landing on them, the same direction in a 360 degree panorama.

For appearances and for added usefulness, we can duplicate the circle layer twice more and center them on the left and right borders of the image.


Just the cleanup remains.  Flatten all the circle layers to one, select all, create layer mask, and apply layer mask.

This is a quick and dirty example, but with a little more time and care, I produced a higher resolution one a couple weeks ago…

Once done, you can drop this into any background in your drawing program that you like, and move it around to get just the right composition.  Distracting distortions in drawing only become evident if you raise or lower the horizon too far from the center of the drawing you’re working on, exposing too much of the lower or upper planes.  Otherwise, panning left to right provides innumerable opportunities to utilize.

Information and sources of inspiration for this post came in part from Vanishing Point: Perspective for Comics From the Ground Up.

Good luck and keep drawing.

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