One Point Perspective in SketchUp

Overview

How to view a model or scene in SketchUp using 1-point perspective.

Process

Camera > Two-Point Perspective

Making sure that any planes that should be perpendicular to the central view point (CVP) are positioned accordingly.

With the camera pointing perpendicular to a plane, the top, bottom, and sides of the plane will form lines that are parallel to the edges of the viewport.

The next task is to make sure that the camera is centered relative to the center of the scene.

With the Advanced Camera Tools (ACT) SketchUp extension installed, create a camera to save and manipulate the view onto the scene.

• Tools > Advanced Camera Tools > Create Camera
• Name the camera, e.g. "1PP"

Note that after the camera is created, a scene is created for the camera which can then be accessed either through the Scene tabs at the top of the project window or through the Scenes palette (Window > Scenes).

Be careful not to use the Orbit tool immediately after using the camera unless the objective is the adjust the save view onto the scene. I.e. if you want to look at something to edit its geometry, it's necessary to first make sure that the camera is no longer selected. I'm not 100% clear on the most efficient, "correct" way to do this, but even if it looks like the camera isn't selected in the Outliner window, click in the Outliner window off any object in the list. Then adjustments applied with the Orbit tool won't change the position of the camera.

SketchUp shows a "active" camera (e.g. one that will be manipulated through the use of the Orbit tool) when there is a small crosshairs icon visible in the scene where the camera is pointed.

Manipulating the view on the scene

Bugs and workarounds

Note that the ACT camera is extremely buggy under Mac OS & SketchUp 2017. For example, even a "locked" camera can be moved using the orbit tool in some cases. The behavior so far is so arbitrary that it's been difficult to document the inconsistencies. Basically, be very careful when manipulating a camera. Take pains to make sure that it's not selected before using the orbit tool. Save a copy of the project to insure the camera angle is preserved somewhere where it can be retrieved.

Aiming the camera can be achieved with the arrow keys along with modifier keys. The instructions are displayed in the status bar at the bottom left of the project window. These controls do not work reliably on Mac OS. They work much better on Windows.

After adjusting the position of an ACT camera with the Move tool, it tends to aim off in some random direction. The camera can be positioned such that it is pointing directly at an object, and the fustrum will indicate that the object is the target of the camera, but after switching to view through the camera, the target will be off to the right of the object instead.

To fix this, while viewing through the camera, right click on the scene and select Edit Camera. It's not necessary to change anything in the dialog, just click the Save button. The target will now be aligned correctly with the position of the camera. (Haven't confirmed that this works on Mac OS.)

Controlling the view

It's easy to accidentally alter the position of the camera while working on the objects in a scene. Adjustments made to direction of the camera made through the camera don't show up in the Undo stack.

Immediately after changing to the saved camera view by clicking on its corresponding scene tab above the main window a small crosshairs icon will be visible on the scene. This is the target of the camera. With the camera in this state any mouse moves will move the camera, and this move is not added to the Undo stack. In order to deactivate the crosshairs icon, select the move tool with the M key, or click on the Move tool in the main toolbar.

A camera can be locked to avoid this either hide or lock the camera after its position has been set: Tools > Advanced Camera Tools > Lock/Unlock Current Camera. I think it's still possible to change the direction of the camera while looking through it even when the camera is locked.

In order to position the camera relative to the center of the scene, use the Orbit tool (or Zoom tool) to back away from the scene far enough to see both the geometry and the ACT camera object (which looks like a little camera within the scene).

• Use the Select tool to select the camera object.
• Switch to the Move tool.
• Select the point on the camera representing the center of the camera lens.
• Lock the Move tool, using either the left or right arrow key, to the axis that is parallel to the front or back plane in the scene.
• Move the cursor over a horizontal edge of the front or back plane of the scene until SketchUp's inference displays the Midpoint of that edge.

The following comes from ACT documentation, but is an unreliable way to manipulate the camera in practice (Mac OS + SketchUp 2017)

To change the position of the camera while looking through the camera:

• Click on the camera's Scene tab. (Tools > Advanced Camera Tools > Look Through Camera)
• Use the arrow keys to move the camera.
• E.g. to "pedestal" the camera (move up & down without changing the tilt) ⇧ + ⌥ + ↑ and ⇧ + ⌥ + ↓