You may have seen a recent video summarizing methods to use multiple line weights in your illustrations.
It’s probably helpful to go into a bit more detail and show more examples.
Using a single line weight (or “stroke width” as it applies to Illustrator’s path art property) is a simple and efficient way to work.
By using more than one line weight, however, your illustrations can have more interest and suggest form.
One method assumes a light source in the upper left. Here edges facing away from the light are given a heavier weight. This was the standard where I worked at Kalmbach Publishing Co. in the 1970s. My mentors there told me it was adopted from a standard for US Patent Office drawings. It was easy to apply using pen and ink, but when they switched from Rapidograph pen to Adobe Illustrator in the 1990s, they switched to a single line weight. Adobe Illustrator, unfortunately, doesn’t lend itself well to multiple line weights, especially if the path is filled.
Here’s an example of an illustration I did using the “Kalmbach” method, drawn in ink at 1.5 times reproduction size. Detail lines were drawn with a 4×0 Rapidograph pen, and the heavy lines were probably a no. 0 or 1 pen. In those days, we typically cut an Amberlith overlay to add a flat tint to the background, which helped separate the subject from the background.
A more common method called “line contrast shading” used in exploded-view parts drawings uses heavier lines on all outside edges of objects. In this example, the bottom of the cube and cylinder are thin lines because they represent the joint between two surfaces. A heavy line would suggest the objects float above the other art. In the case of the round hole, a varied line width makes a smooth transition between the front- and rear-facing edges. Complex illustrations can use three or four line weights. Standards are more like guidelines, actually, that vary between people and between businesses, often based largely on the personal preference of someone with experience and/or influence.
Greg Maxson drew these filter illustrations with pen-and-ink on Mylar for Hyster Co. back in the late 80’s. He explained, “You could really get lost in the detail with pen-and-ink. Lines within an object are thin, exterior object lines are heavier, and exterior object lines that are down and away from the light source are heavier and darker still. The heavying up of the lines down and away from the light source was typically used when illustrating larger equipment, machinery, etc. to give those objects more visual weight. Appropriate for rendering a bulldozer, but less appropriate for rendering the exploded illustration of an ink pen, for example. Of course, super thin interior object lines were/are common when used to represent less than 90 degree radii, and thin broken lines to represent a highlight along an edge, knurling, screening, etc.”
Greg used a three weight treatment on this Raptor suspension illustrations for Car and Driver magazine.
One more piece by Greg Maxson shows his skill at technical illustration using a variety of software, often including SketchUp, Illustrator, and others. Here he adds clarity to the subject with varied line weights, line colors, sometimes sketchy line treatments, and meaningful shading and textures in filled areas.
When AxoTools adds add multiple line weights, it places stroked paths above non-stroked filled paths so weights can change as needed anywhere along the object without affecting the fill. With a simple click of the Axo Line tool, you can toggle weights between thick and thin as necessary. In the coming months, users can expect to see more refinements in AxoTools handling of stroke properties. Please contact me if you have ideas that can make your work faster or easier.
The technique highlights AxoTools’ project-in-place functionality using reference points for quick, accurate placement, ad well as extruding in an axonometric view, measured from a corresponding distance dragged in a flat ortho view.
This visual approach eliminates tedious measuring or counting of isometric grid units. Try it! If you don’t have AxoTools, you can download it here.
The latest update to AxoTools includes three improvements to shaded fills on extruded art. First, curved paths now have a gradient fill to more accurately show the curvature of the surface.
Second, the lighting is based on the location of a theoretical light source, so surfaces are shaded based on their actual orientation relative to the light, and no longer assigned a simple “top,” “left,” or “right” tint or shade.
Third, the light source is user-definable.
When you extrude a path, its fill color is used as the base color for shading values. For each base color AxoTools uses, it creates a gradient that’s stored in the document’s Swatches panel. To use your own gradient for shade values, just fill your starting object with the gradient and extrude it.
There is also a new panel where you can make adjustments to your light and shading, but it’s important to stress that you don’t ever have to fuss with those controls in order to use the new lighting and shading features. Most of you will probably want to stop reading here and just go download the update!
More for “explorers”
For those other few people in the room who want to take things a notch or two higher, the new panel works in three areas:
At the top of the panel is a series of five color well widgets that represent the five stops on the shading gradient ramp for your current document color. The gradient itself represents the range of all possible colors to apply to your fills. AxoTools generates a shaded gradient ramp for each fill color you start with when you extrude with the shading option enabled.
The gradient represents the range of possible tints and shades available based on the angle of the lighting. The first gradient stop represents the lightest highlight color where the light hits it at a 90° angle. Using the default settings, the angle of light on the left isometric plane falls very close to the second stop, which is set to the original color. The third stop represents the shade when the light hits an object on its edge, and stops 4 and 5 represent the rear surfaces, with the last stop showing the effect of backlighting.
The light source’s location is defined with the familiar Tilt and Turn adjustments, which are relative to the viewer. Following these are slider controls for the light intensity, ambient light, and amount of backlighting. As you make adjustments to the lighting properties, the color wells along the top of the panel will preview the results of changes to the intensity, ambient, and backlight lighting properties.
At the bottom right, the “Reset to defaults” button will restore the default settings for all slider controls.
Below the color wells are two buttons relating directly to them. The “Rebuild gradient” button will generate five shades of the current document color.
The “Save gradient” button, I’ll confess, was included for the true “explorers.” If you changed the colors in the color well controls, either by changing lighting properties or using the color pickers in the color wells, this will overwrite the gradient ramp used for the base color.
Please see the online documentation for more information.
Today I released the first in a series of short videos covering topics relating to AxoTools, both using the plugin and doing technical illustration in general. The first video briefly describes different types of projections for the benefit of those who don’t come from a technical illustration background.
The next in the series will cover how to begin an isometric drawing in AxoTools. Other possible topics may include:
Using multiple line weights (including dashed break lines for curved surfaces) to suggest form and mass
Filling art with white to overlap parts
Using flow lines
Fill modes and other Draw panel options
What is that option to rotate ellipses when projecting?
Using the line tool to draw straight lines and to toggle line weights
Entering simple equations in text fields, plus auto-entry of measurements
Use the Extrude tool to draw a drop shadow (but never for an oblique projection!)
What’s the difference between the Transformations panel and Auxiliary projection panel?
Using the Measure tool
How does Project-in-Place work?
What are the Axo Zone tool and Projection Zones for?
If you have other suggestions for short video subjects, please leave a comment below!
AxoTools Qukck Tip: Projections
I’d like to thank Ron Kempke, AxoTools’ co-author, as well as Matt Jennings of Industrial Artworks, and Greg Maxson of Greg Maxson Illustration for the use of their illustrations and advice in getting this video series started.
If you use Hot Door’s CADtools plugin for Adobe Illustrator, you already know how AxoTools complements its extensive set of tools and features with additional options for axonometric drawing. With CADtools to quickly and accurately create orthographic art and AxoTools to project and finish axonometric views, you’ve got the best set of technical illustration tools available for Adobe Illustrator.
AxoTools has improved its integration with Hot Door’s CADtools plugin to share axonometric projections and document scales. To enable this, first select one or both of the CADtools options in AxoTools’ Preferences dialog.
The preferences dialog can be called by double-clicking any of the AxoTools tools or in the menus at Illustrator > Preferences > Graffix Plugins > AxoTools… (Mac) or Edit > Preferences > Graffix Plugins > AxoTools… (Windows).
CADtools offers an extensive array of options for formatting values, but in AxoTools you’ll have to choose from the presets in the Scale units menu in the Preferences dialog.
To import CADtools’ scale or axonometric settings as set in its CADaxonometric panel, first ensure that you have CADtools installed and have checked the AxoTools preference to use CADtools axonometric view. Next select “Load CADtools settings” from the flyout menu in AxoTools’ Projection panel. The first time you do this, it may take a few seconds to make the connection from one plugin to another, but subsequent calls to CADtools will happen very quickly.
If you change the scale or axonometric settings in CADtools, AxoTools will not be alerted and so cannot automatically import the new settings. In that case, you must manually update AxoTools by selecting “Load CADtools settings” again from the Projection panel’s flyout menu. Every time you open or change your current document, AxoTools will look for CADtools to import its settings. If you don’t have CADtools installed, it’s recommended that you uncheck these two settings.
For more information on Hot Door’s excellent CADtools plugin, please visit https://hotdoor.com.
AxoTools 23.1.2 adds three new tools to create axonometric arcs, ellipses, and rectangles. Each tool draws directly on either the left, right, or top axonometric plane, or can be created numerically with a dialog box. As with many other tools in the AxoTools plugin, tap the Alt or Option key to toggle between different planes. dimensions will be scaled and formatted according to the new Preferences settings for the document
Axo Arc tool
As you drag with the Axo Arc tool, the arc will appear highlighted. You can drag the arc forward or backward, left or right. Guide lines will appear to show the location of the arc center as well as a tangent line of the arc’s exit angle. If your preferences select Help text, the tool will also display the current arc’s extent angle and radius.
As you drag, press the Alt or Option key to adjust a fixed radius, or press the Ctl or Cmd key to change the arc’s starting angle. Press the shift key to constrain the arc’s extent to increments of 45°.
Click with the tool to display a dialog box to create an arc numerically. The Start angle represents the angle before projecting the arc to its axonometric plane, so you won’t need to hassle with converting angles on the screen to simple flat art. For example, a Start angle of 0° in the dialog would be drawn at 30° in an isometric top or right side view, and a 90° extent makes a quarter of a circle, regardless of the angles on the screen. Here, too, you can specify the radius of the arc with dimensions given in units you specify, such as feet or meters, and scaled to the current document ratio defined in your AxoTools preferences. Finally, choose whether the arc should curve to the left or to the right.
Axo Ellipse tool
As you drag with the Axo Ellipse tool, the ellipse will appear projected onto your current axonometric plane. If your preferences select Help text, the tool will also display the current width and height using the units specified in your preferences and scaled to your document scale.
As you drag, press the Alt or Option key to anchor the ellipse at its center point. Press the shift key to constrain the ellipse to a circle.
Click with the tool to display a dialog box to create an ellipse numerically. Enter a height and width, which will be scaled according to the document scale in your preferences. You can also enter a depth to extrude the ellipse to create a cylinder. Stroke widths and shaded fills will be adjusted according to your Axo Draw settings if you have that options set in your preferences.
Axo Rectangle tool
The Axo Rectangle tool works similar to the Axo Ellipse tool, except that it draws a rectangle. Like the Axo Ellipse tool, pressing the Shift or Alt/Option keys work as they do in Adobe Illustrator’s built-in Ellipse or Rectangle tools, only the art is drawn on an axonometric plane.
Click with the tool to display a dialog box to create a rectangle numerically. Enter a height and width, which will be scaled according to the document scale in your preferences. You can also enter a depth value to extrude the ellipse to create a box. It can be styled according to your Axo Draw settings and preferences settings.
These three tools have been among the most requested features, so it’s exciting to now make them available. Tutorial videos will be coming to demonstrate how to use them.
AxoTools now includes an Axo Shear tool that will allow you to shear artwork that’s already been projected onto an axonometric plane. It functions similar to Adobe’s Shear tool in that its default anchor point is the center of the selection, but you can click to place the anchor anywhere you’d like.
The plugin will display a cube annotation with one of the three axonometric faces highlighted. Simply tap the Alt/Option key to choose the plane you’re working on. Drag to shear the art, and the current shear angle will be shown near the cursor. Press the Shift key while dragging to constrain the shear to increments of 15°.
To shear art numerically on a projected plane, Alt/Option click on a location for the anchor point of the operation. In the dialog box that appears, fill in the shear amount, the axis angle to shear on, and the face upon which to shear.
The new tool is available in the current version of AxoTools for Adobe Illustrator 2019 – 2022. You can download it here for either Mac or Windows.