3D Sketching: What Design Engineers Need to Know

Designers of all types use pencil and paper sketching to focus their thoughts. But can CAD tools allow the same type of experimental freedom?
When it comes to 3D sketching, they do. And they’re getting better.


When it comes to nearly every CAD model, sketching is the basis for creating a 3D object.

While 2D sketching can ably define extrusions, holes, paths and other features, its uniplanar restriction is cumbersome, if not unworkable, when drawing some complex shapes.
SOLIDWORKS includes a 3D sketch tool to make the process of creating geometry that snakes or slides through 3D dimensions.

Just like its 2D counterpart, the 3D sketch tool creates geometry by using points, lines, splines and any other sketchable shape to define a profile. What’s different about 3D sketching is that instead of drawing on a single plane, 3D sketching can exist on multiple planes simultaneously.

SOLIDWORKS allows users to toggle through the XY, YZ and ZX dimensions of the drawing environment by hitting the tab key. Once in a desired spatial alignment, geometry can be added to any area that falls within that dimension.

Wire Routing: 3D Sketches Greatest Feat

So, how does 3D sketching actually help designers? One of its biggest assets is its ability to quickly create wires, pipes and tubing that can to snake through space in three dimensions.
Modeling a cable or any other off the shelf part may seem like a waste of a designer’s time, but they can be valuable.


Looking to find the most efficient route to connect two electrical systems within a product? With 3D sketching users can build that wire, connect the systems and measure the length of product they’ll need to wire up their device.

With that info in hand users can order more efficiently and reduce the overall cost of a product by not wasting wire or having to stock more material than needed.

In addition, CAD models of wires can also be used to create wiring diagrams. Those diagrams can then be used to instruct field technicians or customers on how to properly install components.

Complex Surface Shapes


But beyond wiring are there other uses for 3D sketching?

In normal 2D modeling, complex surfaces can be made by drawing multiple sketches that are then related to one another by guide curves.

To union all of these sketches and guides into a shape, designers have to invoke commands like boundary surfaces, lofts and sweeps.

Even after all of that work, sometimes SOLIDWORKS finds fault with your geometry and can’t build a surface from a compilation of sketches. In those instances, 3D sketching can be the only way to create the geometry you require.

Or is it?

A 3D Sketchbook

Recently, Dassault decided to add its Natural Sketch program (once solely available in CATIA) to SOLIDWORKS’s Industrial Design Package.

Unlike SOLIDWORKS’s parametric approach to sketching, Natural Sketch is a drawing program that’s controlled via stylus and touchscreen, which allows designers to create shapes from lines that are sketched more naturally.

What’s most impressive about Natural Sketch is that with a few simple strokes a designer can generate a 3-dimensional conceptual model built from a series of 2D sketches. That model can then be used to interrogate a design, refine a concept or form the basis for a 3D CAD model that can be built using a parametric surface.


Apart from being a tool for generating new models, Natural Sketch also has the ability to sketch directly onto previously create products making it an ideal tool for redesigning a line.
Similar to the way an original sketch can be transformed into parametric geometry, added surfaces can be knit onto older models to update a product quickly.

Today, 3D sketching tools are becoming easier to use and more useful when it comes to design.

While both 3D Sketching and Natural Sketch have advantages over the other, Natural Sketch looks like it’s method for creating geometry is likely to win out over other 3D sketching tools.

Simply put, Natural Sketch provides a more intuitive way to create geometry than the 3D Sketch tool does. Sketching has always been important to design. The closer 3D sketching tools come to imitating a pen and paper interaction, the better they become at serving their core purpose, creating and expressing an idea in the most efficient manner possible.

About the Author


Kyle Maxey is a mechanical designer and writer from Austin, TX. He earned a degree in Film at Bard College and has since studied Mechanical and Architectural drafting at Austin Community College. As a designer Kyle has had vast experience with CAD software and rapid prototyping. One day he dreams of becoming a toy designer.

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