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Linear Perspective

Isoaxial perspective is great for top-down 2D game art, but linear perspective is better if you want to create more realistic scenes.

In this mode, you can use three rulers: two lines parallel to the ground plane and a vertical line.

It takes the following parameters:

  • Zoom in/Out images – If you are using an older version of Photoshop than CS3, or any other art application, you must set this parameter when zooming in or out to match the value of the canvas zoom, otherwise the perspective lines will no longer align with your scene. It is also recommended to draw a separate mark under the center point of the view so that you can readjust your image. For applications that cannot automatically track, you can at least enable Settings -> Blank key pan offset ruler center menu to keep center aligned while pan canvas. (In Photoshop, be sure to uncheck enable tap pan in the general TAB).

  • Display radius – This parameter defines the radius (in pixels of screen space) of the circle where the cone intersects the image plane. The center of the circle is the intersection of the viewpoint direction (or line of sight) with the image plane. You can move the center by dragging the center control point. You should set this parameter so that the view circle covers most of the canvas at 100% zoom.

  • Line of sight – This represents the field of view visible within the view circle. A small value of this parameter will produce a telescopic view in which perspective effects will be minimized (the vanishing lines will appear parallel). A larger value projects more of the world into your field of vision and exaggerates perspective. Note that objects drawn from a 60 degree view circle may start to look unnatural and distorted, but this can be used for artistic effects.

  • Display tilt – This parameter controls the vertical tilt of the line of sight. It corresponds to the rotation Angle about the X-axis and controls the green ruler.

    • When set to 0, the view direction is parallel to the ground, and all the straight lines up or down in the scene are drawn vertically and parallel on the canvas.
    • Positive values point the eye to a point below the horizon. This is sometimes called a “bird’s eye view.” In this case, the upward and downward lines will not be parallel on the canvas and will meet at a vanishing point below the horizon (which will now be above the center of the view);
    • Negative values point the eye to a point above the horizon. This is sometimes called a “bug ‘s-eye perspective.” In this case, the upward and downward lines will not be parallel on the canvas and will meet at vanishing points above the horizon (which will now be below the center of the view).

  • Line 1 Angle – This is the Angle of the red ruler line, measured from the direction of the field of view.

  • Line 2 Angle – This is the Angle of the blue ruler line, measured from the direction of the field of view.

  • Select straight line mode – this controls line breaking in the same way as isometric ruler.

  • Box mode – When enabled, your pen position will be fixed to a 3D bounding box while drawing, helping you close the box quickly without going over it. When you draw once on each axis, the size of the box is automatically determined. When you lift the pen, the size resets.

Note that you should set three view parameters (radius, field of view, tilt) when you start drawing, and then do not change them again as you work in your scene.

You will want to change the angles of lines 1 and 2 to draw objects with different rotations. These lines are always parallel to the ground plane, so they cannot be used to draw slopes such as slopes or roofs. To do this, you should use a perspective ruler to build an axially aligned bounding box, and then use a parallel or link-line ruler to draw slashes. If the link button is enabled, when you change either line between line 1 and line 2, the Angle between them remains the same.

Hold down the Ctrl key to display the Angle control point, measurement point unit distance control point and freeze mode switch control point. You can slide the center control point along the X or Y axis while holding down Ctrl. While doing this, the freeze point remains in the same position on the screen. If you forget to mark it on the canvas, this will help you reset the center position: set the freeze point to one corner of the drawing object, then slide the center point until the vanishing line aligns with the edge of the object.

Clicking the Freeze mode control point (or pressing the relevant keyboard shortcut) will create a fixed reference frame at your pen position. Just like an isometric ruler, you can use this and measurement points to subdivide sections precisely.

Fisheye Perspective

Linear perspective projects 3D lines to 2D lines, fisheye perspective projects them to 2D curves. This perspective mode has a fixed Angle of view of 180 degrees. Half of the earth is effectively projected onto the field of vision.

This ruler won’t let you change the Angle of the line. You can choose between a horizontal line, a vertical line, and a line that points to the center of the view.

Hold down the control button to display the measuring point unit distance control point and freeze mode switch control point

Clicking the Freeze mode control point (or pressing the relevant keyboard shortcut) will create a fixed reference frame at your pen position. As with isometric and linear perspective rulers, you can use it and measuring points to precisely subdivide sections.