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Spatial Unit Type

This template project presents an overview of how each unit type interacts with the characteristics of the selected Main Display.

LabMaestro allows you to define the dimensions of visual elements using pixels, centimetres, or degrees of visual angle units. This project assumes that the attached Main display reports its physical size correctly and that the specified viewing distance is 57.3 cm. For more information, see the Displays documentation page.

First, download the template project here: SpatialUnitsTemplate_V1.lm

Warning: In LabMaestro Public Beta 1 through LabMaestro 1.7, when first opening a *.lm file, the preview may not be immediately refreshed. This may occur when property fields contain Expressions, or references to custom variables defined within the property panel of Timelines. To refresh the preview, without executing the entire experiment, click on Play Timeline. Note that variables defined by Methods may have a preview option available from their own method tab.

Launch the experiment and examine the example stimuli:

  • The first stimulus is defined in pixels. If the video mode uses the display's native resolution, you can count the number of physical pixels to ensure they match the requested stimulus geometry.

  • The second stimulus is defined in centimetres. Use a ruler to check that the physical size matches the requested stimulus geometry accurately.

  • The last stimulus is defined in degrees of visual angle. A stimulus occupying one degree of visual angle when viewed from 57.3 cm away should measure 1 cm wide. You can experiment with viewing distance to see how the size of stimuli defined in degrees of visual is adjusted in consequence.

You can also change the unit of each example stimulus to see how LabMaestro automatically converts requested values from one unit to another.

We recommend specifying dimensions in degrees of visual angle when defining stimulus dimensions. This simplifies working across multiple computer stations and sharing project files with colleagues because dimensions will be adjusted while taking into account the requested viewing distance and the physical dimensions of the current main display.

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