It is possible to make scalable technical drawings with Photoshop by using the shape tools.
Adobe designed Photoshop primarily as a photograph editing tool, designed for editing and processing bitmap graphics like photographs. However, Photoshop also includes tools for creating vector graphics, which enables you to draft scalable technical drawings and plans. Vector graphics made in Photoshop are not easily transferable to other drafting programs. Although its capabilities are no substitute for professional tools like AutoCAD, Photoshop can be a suitable solution for producing printed plans or plans to be rendered to bitmap graphics for distribution.
1. Create a new Photoshop document. If you already know the desired printed size of your drawing, specify those dimensions for the width and height, and a pixel resolution compatible with the printer. Otherwise, create a document with enough pixels to fill your work area. One of the principle advantages of working with vector graphics is that they can be scaled later without loss of quality.
2. Activate the “Grid” item in the “Show” submenu of the “View” menu to reveal the grid. Also activate the “Grid” item in the “Snap To” submenu of the “View” menu. Choose the “Guides, Grid, & Slices…” item in the “Preferences” submenu of the “Edit” menu to reveal a dialog with options related to the grid. The most important settings are the “Gridline Every:” and “Subdivisions:” fields; specify them according the overall scale and level of detail required for your plans. By setting up a grid before you begin and ensuring that your lines will snap to it, you can facilitate rapid, well-ordered drawing in a similar fashion to specialized software drafting tools. If you need to change the scale of the grid later in the drawing process (by changing the “Subdivisions:” field), do so in even multiples to avoid shifting the grid off elements you’ve already placed.
3. Select the shape tool by pressing the “U” key. Set up the details of the shape you’d like to draw in the options bar (just beneath the menu bar in the default workspace). Ensure the “Shape Layers” button is selected; it is the leftmost of a set of three buttons on the left side of the options bar. It shows a square with small boxes on its corners. From the next set of buttons, choose the shape you’d like to draw. Each shape may reveal a different option to be specified to the right of these buttons. For example, selecting the polygon tool reveals a field to specify the number of sides of the polygon. The next set of buttons controls how different shapes in the same layer will intersect. These buttons are not usable unless you’re adding to a layer with shapes already in it. Choose the white square with the red slash through it from the “Style” drop-down menu. Choose a fill color from the rightmost button on the options bar. If you’re drawing with the line shape, this option will determine the line’s color.
4. Click and drag in the document to draw a shape. Notice that it automatically snaps to the grid; this will help keep your plans ordered and aligned. Notice also that the layer appears differently in the “Layers” panel; this means that Photoshop is distinguishing it as a vector layer. If you want to see only the outlines of a shape like a rectangle or polygon, set the “Fill:” field to 0% on that shape layer and add a stroke effect by right-clicking the layer and choosing “Blending Options…” to change the layer’s style properties (use the “Center” option for the positioning of the stroke to get an even line). Further shapes drawn in this layer will now match this style. If you’re just drawing with lines, leave the “Fill:” field for the layer at 100%. To add more shapes to a shape layer, select the layer and the shape tool, then activate the second shape intersection button in the options bar described in Step 3 (if the buttons are not usable, click the layer’s graphical preview box in the Layers panel to make sure the shape layer is selected correctly). The shape you then draw will intersect with any shapes already in the layer, instead of generating its own layer, and will share the style of all the shapes in that layer.
5. Use the “Path Selection” tool to move shapes and lines you’ve drawn by clicking and dragging them. You can quickly select this tool (or its counterpart, the “Direct Selection” tool) by pressing “A”. To resize or rotate a shape or group of shapes selected together, press “Ctrl-T.” Drag the boxes along the edges of the selection. The options bar has several alignment buttons you can use while multiple shapes in a layer are selected with this tool. You can press the “Combine” button to merge the shapes in a layer into a single shape.
6. Organize the layers in the document to reflect any hierarchical elements in the drawing, such as multiple elevation sections in an architectural plan. You can easily hide or show different layers to explore the different parts of a complex drawing.
7. Save the plans in the Photoshop document format (PSD) to continue to be able to edit your shapes in vector form. For purposes of distribution, save a copy of the document using a bitmap format like JPEG or TIFF to render the shapes into pixels viewable with any image viewer.