Perspective Drawing with Lazy Nezumi Pro

Perspective Drawing with Lazy Nezumi Pro

If you want to draw convincing 3d environments, vehicles, and even people, mastering perspective is a must. Traditionally, setting up for a perspective drawing can be tedious and time consuming, with vanishing points going way off the page, and messy construction lines everywhere. Lazy Nezumi Pro's perspective preset will hopefully make this process faster and easier!

This particular preset uses a type of projection called Linear Perspective (Isometric and Fisheye projections are also available as different presets). It generates a set of rulers that connect your current pen position to fixed vanishing points. Your lines then snap to these rulers when you draw, helping you quickly construct perspective-correct objects in your scene.

  1. Parameter Setup
    1. Image Zoom
    2. View Radius
    3. Field of View
    4. View Tilt
    5. Line 1 and Line 2 Angles
    6. Line Select Mode
    7. Box Mode
    8. Overlay Control Points
    9. Keyboard Shortcuts
  2. Working in 3D
    1. Understanding Tick Spacing
    2. Constructing a Box
    3. Extending Sections
    4. Subdividing Sections
    5. Perspective Symmetry
    6. Perspective Circles
    7. Line Attenuation
  3. Further Study

1. Parameter Setup

If you open the Ruler - Perspective preset's Rulers section (by clicking on the little arrow icon), you'll see several configurable parameters. This section will explain what these parameters do, and how to choose appropriate values for your perspective drawings.

Perspective Parameters

1.1 Image Zoom

If you are using a version of Photoshop older than CS3, or any other art application, you must set this parameter to match the value of your canvas zoom after you zoom in or out, or the perspective lines will no longer align with your scene. It's also recommended to draw a mark under the view center point in a separate layer, so that you can realign your image.

With Photoshop CS3 and up, your document's pan and zoom will be tracked automatically (this was added in LNP update 18.03.08).

For apps where automatic tracking is not possible, you can at least enable the Settings/Spacebar Pan Offsets Ruler Centers menu to keep your center aligned while you pan your canvas (in Photoshop, be sure to uncheck Enable Flick Panning in the general preferences tab).

1.2 View Radius

This is the first parameter you should adjust when setting up for a new perspective scene. It defines the radius (in screen-space pixels) of the circle which is the intersection of the cone of vision with the image plane. You should set this parameter so that the view circle covers most of your canvas at 100% zoom.

The center of this circle is the intersection of the direction of view (or line of sight) with the image plane. It can be moved by dragging the little overlay circle graphic, or by using a keyboard shortcut. Cone of Vision

1.3 Field of View

This represents the field of view that is visible within your viewing circle. A small value for this parameter will produce a telescopic view, where the perspective effect is minimized (vanishing lines will seem parallel). A larger value is equivalent to a wide angle camera lense, and will project more of the world to your view circle. Note that objects drawn further out from a 60° viewing circle can start to appear unnatural and distorted, but this can be used for artistic effect.

Field of View

Choosing an appropriate value for this parameter really depends on what kind of scene you are drawing. Typically, you will use a larger value for landscapes, and a smaller value for close-up shots. If you are unsure, try drawing some test scenes at both extremes to get a feel for the difference. With a large field of view, closer objects will appear much larger than they actually are. You may also want to study photographs taken with both wide angle and telephoto lenses. The smaller the focal length of a camera lens, the wider the field of view.

If you want to draw with a 180° field of view, be sure to check out the Fisheye Perspective preset!

1.4 View Tilt

This parameter controls the vertical tilt of the line of sight. It corresponds to camera's angle of rotation around the x axis, and directly controls the orientation of the third (green) ruler.

  • When set to 0, the view direction is parallel with the ground, and all the lines going straight up and down in the scene are drawn completely vertical and parallel on the canvas.
  • Positive values make the line of sight point towards a point below the horizon. This is sometimes referred as "bird's eye view". In this case, the lines going up and down will not be parallel on the canvas, and will meet at a vanishing point below the horizon line (which will now be above the center of the view).
  • Negative values make the line of sight point towards a point above the horizon. This is sometimes referred as "worm's eye view". In this case, the lines going up and down will not be parallel on the canvas, and will meet at a vanishing point above the horizon line (which will now be below the center of the view).
View Tilt

1.5 Line 1 and Line 2 Angles

These parameters control the angles of the first two perspective rulers. Contrary to the vertical ruler (controlled via View Tilt), these are used for drawing lines that are parallel to the ground. They are defined by their angle with respect to the line of sight.

Controlling the rulers via their angles allows you to place rotated shapes anywhere in your scene, without worrying about where the actual vanishing points should be placed. For example, if you want to draw a square, the only requirement is that the difference between Line 1 and Line 2 angles is 90. But they can be rotated any way you like: -45/45, -30/60, -10/80, etc.

While the view parameters (radius, field of view, and tilt) should not be changed after you've setup your scene view, having some variation in the orientation of your objects by changing Line 1 and Line 2 angles will go a long way in making it appear more natural. To speed things up, these angles can be rotated together when the Angle Link button is checked (maintaining their separation angle constant) or separately via keyboard shortcuts, or via their control points while holding the control key.

Rotating Line 1 and Line 2

You can't use Line 1 or Line 2 for inclined lines that are not parallel to the ground, such as ramps and roofs. Instead, you should construct an axis aligned bounding box using the perspective rulers, and then switch to a different ruler preset to draw them. Be sure to use separate layers for your internal construction lines, so you can easily hide them at the end.

The following example shows how you can use the Radial Lines ruler to construct a pyramid. Use this method when you know exactly where the vanishing point is.

Tilted lines with the Radial Lines preset

The following example shows how you can use the Vanishing Lines ruler to draw a tilted roof. Simply Line up the control lines with the two edges. Use this method when you can't easily find the vanishing point.

Inclines with the Vanishing Lines ruler

1.6 Line Select Mode

The Line Select Mode parameter determines which ruler is chosen when you draw:

  • Manual start & change: You have to manually choose which ruler to start drawing on by pressing the shift key. You can change lines while drawing by pressing the control key.
  • Auto start, manual change: The starting ruler will be chosen automatically based on the direction of the first few samples of your line. You can change directions while drawing by pressing the control key.
  • Auto start & change: Same as the previous option, but you can change lines while drawing without pressing control. This mode is great for fast 3d sketching, but not recommended if you need precise control.

1.7 Box Mode

When this is enabled, your pen position will be clamped to a 3d bounding box while you draw, helping you quickly draw perfect boxes without lifting the pen and without your lines overshooting at the corners. The dimensions of the box are determined automatically one at a time as you first draw on each axis (press control to change axis while drawing). The dimensions are reset when you lift the pen.

Box Mode

1.8 Overlay Control Points

Many of the parameters can be controlled directly via on-screen overlay control points. The view center control point is always visible. When you hold the control key, you can interact with the other control points:

  • Line 1 and 2 Angles These control points let you rotate Line 1 and 2. Holding the shift key will clamp the angles to 5° increments.
  • View Tilt This lets you tilt the view up and down. Holding the shift key will clamp the angle to 5° increments.
  • Measure Point Unit Distance This lets you increase or decrease the distance between the ticks, by sliding the point along the line.
  • Freeze Mode Clicking this control point will toggle a fixed axis base point for quick 3d measurements and comparisons.
  • Grids Clicking this control point (only available while in freeze mode) will cycle through the different grid options: XY, ZY, XZ, off.
  • View Center While holding control, you'll notice the center point turns yellow. In this mode, you can slide it along the X or Y axis. Holding the shift key will also allow for more slow/precise movement.
Perspective Control Points

When you slide the view center control point (while holding control), the Freeze Point stays at the same place on the canvas. This is useful in case you forgot to mark the center of your perspective scene, and are trying to get it back: hover over the corner of a pre-drawn object in your scene, activate Freeze Mode, then slide the view center control point horizontally and vertically until the vanishing lines line up with the object edges.

Finding the center

While in Freeze Mode, you can also turn on one of the grids These can help you better visualize and plan out your perspective scenes.

Clicking on the Grids control point will cycle through the 3 grid planes: XY, ZY, XZ, off. You can adjust the size of the grid by using the yellow measure distance control point. The number of lines can be controlled via the Overlay settings window.

Perspective Grids

1.9 Keyboard Shortcuts

This preset has several useful keyboard shortcuts that can be assigned via the Settings/Edit Shortcuts menu's Ruler Shortcuts tab. Please note that these shortcuts will not override any functions that are already assigned to keys in your art application, so you'll want to use keys that don't already have a function. These will be active as long as the Settings/Ruler Param Shortcuts menu is checked. You don't have to set keys for all of these, but depending on how you work, you might find some of them very useful.

  • Move Center: Hold key down while moving your pen to move the center of the current ruler preset (this works with any script that uses a center position).
  • Perspective - Rotate Line 1: Hold key down while moving your pen from left to right to rotate Line 1 continuously.
  • Perspective - Rotate Line 2: Hold key down while moving your pen from left to right to rotate Line 2 continuously.
  • Perspective - Rotate Line 1 & Line 2 (fixed increment): Two shortcuts to rotate Line 1 and Line 2 together in fixed increments. You can set the angle of rotation for each direction.
  • Perspective - Rotate vertical tilt: Hold key down while moving your pen up and down to rotate the vertical tilt of the view.
  • Perspective - View Radius: Hold key down while moving your pen from left to right to change the view radius.
  • Perspective - Field Of View: Hold key down while moving your pen from left to right to change the field of view.
  • Perspective - Freeze: Press key to toggle freeze mode, to create a fixed frame of reference at your pen position.
  • Measure point unit distance: Hold key down while moving your pen from left to right to change the measure point unit distance.
  • Select Line: This key changes the current starting line when Line Select Mode is set to manual.

If the center of any ruler preset goes off-screen and you can't seem to get it back, you can use the Set or Reset Scripting Center Pos shortcuts to reset it. These can be configured via the Settings/Edit Shortcuts menu's General Shortcuts tab. Please note that these shortcuts however are global, and will override any previously set function.

If you want panning with the spacebar key to offset the center automatically, enable the Spacebar Pan Offsets Ruler Centers setting.

2. Working in 3D

The tick markers on the rulers are called Measure Points. These will let you measure and compare relative distances in your 3d scene. In the Overlay Settings, you can set their quantity, size, and unit distance. You can also change the unit distance via keyboard shortcut, or the overlay control point. This will come in handy later.

Configuring Measure Points

You can choose to ignore them or turn them off, but if the relative proportions of objects in your scene are important, then you'll need to understand how to use them.

2.1 Understanding Tick Spacing

Since an infinite number of 3d points can project to the same 2d point, the system can not know the depth of your pen position in the 3d scene based on its 2d screen position. Because of this, the chosen convention is to have the depth be equal to the image plane's depth for all 2d screen positions when you are not drawing. Only once you start drawing can the system know the current depth of your position on the line (relative to its start), and so you will see the ticks get closer together as you near the horizon, or further apart if you draw away from the horizon.

A side effect of this is that the same number of ticks will not necessarily represent the same 3d distance if measured from different 2d screen positions. This would only be true if the 2d positions were at the same depth in the scene, like the two ends of a vertical line (assuming the view has no vertical tilt).

The following image illustrates this. Note how the sides of the cube measure 3 ticks if measured from a front corner, but only 2.5 ticks if measured from a back corner.

Comparing Tick Markers

2.2 Constructing a Box

Because of this, if you are drawing a 3d object while using measure points to set its dimensions, you will want to count ticks from the same 2d screen position. For example, if you wanted to draw a 3x4x5 box, you would choose a corner, then draw a 3 tick line in one direction, then draw a 4 tick line and a 5 tick line in the other directions, always starting from the same corner. Once your 3 main corner lines are drawn, you can then ignore the measure points when drawing the remaining lines (since you'll be starting from different 2d positions, the tick distances won't match). Instead, you should simply draw until an opposing ruler lines up with the end of an established corner line.

Drawing a box using Measure Points

2.3 Extending Sections

If you do want to draw while measuring from a different corner, you'll need to adjust the measure point unit distance. For example, if you wanted to double one of the dimensions of the box, you can place your pen over the desired center corner, and use the shortcut to change the measure point unit distance until a tick marker lines up with with the starting corner. You can then count the number of ticks between these corners, and draw a line on the other side using the same number of ticks.

Extending a Box

While it's important to know the previous method, there is another method that is sometimes faster. If you enable Freeze Mode (via the overlay control point, or keyboard shortcut) while your pen is over a corner of your object, you will get a fixed frame of reference at that position, and a new set of rulers (without measure points) will start following your pen. You can now find the right distances by lining up the rulers with the fixed measure points.

Extending a Box using Freeze Mode

2.4 Subdividing Sections

While in Freeze Mode, you can also quickly divide a section into equal parts. Simply change the measure point unit distance until the section is cut into the desired amount of parts, and line up the new rulers to draw them. This method can be used to quickly find the center of a section, without having to draw diagonals.

Dividing Boxes using Freeze Mode

2.5 Perspective Symmetry

When working in perspective, foreshortening can make it difficult to estimate the proportions of symmetric objects, especially when they aren't simple boxes. This is another thing Measure Points and Freeze Mode can help you with.

For example, if you want to make sure you are drawing the other side of a symmetric curve correctly, you can use the measure points and the perspective ruler guide lines to project a number of points from the curve to the other side of the symmetry axis.

First, you enable Freeze Mode at a position where one of the axis aligns with a side of your bounding rectangle (in the following example, the red horizontal axis lines up with the bottom), and another axis is at the center of the rectangle (in the example, the blue vertical axis will be the axis of symmetry). You then change the measure distance so that you have a couple tick markers on each side of the symmetry axis (three is usually good, but you may need more if you have a complex curve). At each of these tick markers, you line up the vertical ruler and find the corresponding point on the curve. From that point, you draw a line until the vertical ruler lines up with the corresponding tick marker on the other side. You can then use these projected points as guides when drawing the other half of the curve.

Mirroring a Curve using Freeze Mode

2.6 Perspective Circles

Another thing that can be tricky is drawing circles in perspective. It's important to try to get this right however, or the viewer will immediately know that something is wrong with the drawing.

Viewed in perspective, a circle appears as an ellipse. This is great, as an ellipse is not hard to draw (and you can use Lazy Nezumi Pro's Ellipse Ruler), but you still need to figure out how to correctly set the center, degree, and rotation, for it to look right.

As you get more practice at drawing in perspective, you will develop a feel for the correct shape and orientation of the ellipse required. Remember that it doesn't have to be perfect, it just has to look right. Here are some tips that will hopefully help:

  • The center of the ellipse will almost never match with the center of the circle, but it's a good starting point.
  • Ignore the major axis of the ellipse. It almost never intersects anything useful.
  • The minor axis of the ellipse should be loosely aligned with a line coming out of the circle center, which is perpendicular with its plane (like a wheel axle). Note that the further out you are drawing from the view center, the less they will align.
  • The ellipse should touch the perspective center point of each side of the circle's bounding square.
  • The ellipse should also touch the four corners of a concentric square that is 7/10 the size of the bounding square. You can easily construct this square by changing the measure point unit distance so that you have 10 tick marks on each side of the center, and then count 7 ticks from the center for each side (in the following example, we used a little under 3/4 for clarity). This step gives you four additional points to line up with, and can help fine tune the placement.
Drawing a Circle in Perspective

2.7 Line Attenuation

If you are drawing large structures, attenuating the line size as you get closer to the vanishing point can really contribute to the impression of depth.

If you have your pen pressure mapped to the brush size, you can do this yourself by slowly easing off the pressure as you draw the line. But this can be hard to control, and if you're drawing more than one line, it'll be hard to get a consistent look.

Lazy Nezumi Pro can help with this! While you have the perspective ruler enabled, enable scripting, and select the perspective fade mode from the Pressure category. Your pressure will now be automatically attenuated as you get closer to a vanishing point. This lets you draw with a natural, constant pressure feel, and will give you consistent attenuation for all your lines. The attenuation parameter allows you to adjust the rate at which the pressure gets attenuated.

Note that for best effect, you should also decrease your brush size when drawing lines that start further away in depth.

Line Attenuation

3. Further Study

The techniques described in the previous section can be used to build complex objects in perspective. You can either start with a bounding box and cut sections into it (like sculpting), or you can start with XYZ plane views, and project out from them (like building a model skeleton). This is generally called form building.

You can use these techniques as much as needed: sparingly to just make sure you have the correct general proportions, or more like an architect planning exact placement and dimensions of all the elements in a scene (altough at that point, it might make sense to use 3d software).

You can learn more about these techniques by checking out Scott Robertson's excellent How To Draw book. He also has a nice collection of tutorial videos on his Youtube channel.

Also be sure to check out Rene Aigner's excellent video: The Power of Boxes, in which he uses these techniques to draw vehicles: