Shop technology and 3-D CAD: Using props for adding scale to a presentation

Figure 1a
What good is a product illustration that might be cute but does not inform?

Editor's Note: If you would like to download the 3-D CAD files associated with this column, click here.

The invention shown in Figure 1a is represented fairly well and is an intriguing image. However, it is difficult to assess the function or scale of the mechanism. Figure 1b puts the device into a meaningful context by adding a familiar prop to the scene—a classical guitar.

We wish to acknowledge Tim Johnson for allowing us to use his guitar accessory as a subject of discussion. This is the real deal. Tooling and manufacturing are complete. Johnson has customers and is taking orders for this newly released accessory. His website, www.guitarest.com, has more information if you’re into playing classical guitar with comfort.

My role in this project included industrial design, manufacturing, engineering, and graphic arts. While working with Johnson to translate his inspiration into a patented, and more importantly, marketable item, I produced complete and accurate 3-D models of the product line using mainstream 3-D CAD software.

Business and CAD Mix Well

The CAD data became vital to Johnson’s business operation. As the design evolved, the consequences to inventory were well-managed:

• The top-level bill of materials (BOM) was valuable for identifying and purchasing hardware.
• The BOM also helped with creating a master costing spreadsheet.
• Vendor activity, which involved a machine shop, a sheet metal shop, a plastic shop, a painter, a plater, and an assembler, was coordinated using a spreadsheet that was derived from the CAD BOM.
• The STEP files (and PDFs of 2-D fabrication drawings) exported from those CAD models were used to make the tooling for vacuum forming as well as for the CNC machining and laser cutting of the metal parts.
• The 3-D CAD models were used to create still shots for Johnson’s printed literature. They’ve been used again to create the images for this column.

With the creation of still shots in mind, please compare Figure 1b to Figure 1c. Without the mannequin in Figure 1b, the leg rest remains mysterious. It might be some kind of repair clamp or sound damper. (It is neither of those things.) We found that the mannequin sitting in a chair made it easier for the first-time viewer to appreciate the function and appearance of the product.

Those props in Figure 1c, hombre.sldasm and chair.sldprt, were downloaded from www.3dcontentcentral.com. Acknowledgment to Josemari de la Iglesia for the human poser and to Tuyen Ha for the chair.

Figure 1d is a zoom-out from Figure 1c. We added a spotlight to bring the leg rest out of the shadows. We found Figure 1c to be more successful than Figure 1d mostly because of the mannequin. The “un-realism” detracts from the message. This scene does, however, show both the armrest and the leg rest in meaningful context.

Center the Attention: Minimize Distraction

Since up-close was good in Figure 1c, we tried the same with the armrest in Figure 2a. The mannequin’s shirt is textured with yellow “tread plate.” When viewed closely, the mannequin is a strange combination of realism and poor choice of textures for this scale of rendering. Figure 2b takes advantage of distance to make the texture less of a standout. Cropping puts the mannequin into the background. We also put “skin” on his elbows and knees to remove unrealistic distractions from the image.

One of our focus groups suggested getting rid of the props altogether, keeping it simple and just showing what is for sale. The result is Figure 2c.

Figure 1b
The use of a prop can make it easier to understand what the product does. In this case, a guitar as a prop gives a hint that the item in Figure 1a might be a guitar accessory.

On a computer, it is easy to toggle between Figure 2b and 2c to make the product really jump out. We made an animation that did just that, but it felt like a flash-bulb experience instead of something helpful.

With our exposure to the previous images, Figures 3a and 3b show a product with recognizable functions. Our focus group found these images to be mysterious without context and suggested using them in an owner’s manual. Our advice is to use them in the right context.

Motion Emotion

In addition to lovely still shots, we also created animations using the CAD database. The thumbnail in Figure 4 gives a hint of what’s in our training video. You’ll see the invention attached to a guitar in the lap of a mannequin.

This snippet from a video shows the mannequin playing the guitar with moving arms, head, and hands. The video briefly shows the armrest’s hinge adjustment and its placement options, then moves through all three of the axis adjustments for the leg rest, and closes with a fly-around showing the poser’s performance from many points of view.

As a quick instruction manual for new owners, that video has been effective. As aspiring movie producers and directors, we applied our lessons learned from the still shot production to creating the scenes, or views, for the animation storyboard/timeline.

What did we learn?

1. Focus on telling the story of why as much as what.
2. Always keep the star of the show the center of attention.
3. Pause and go slow for comprehension. Speed is for drama. Camera moves change the point of attention.

Bad Results

Sadly, some mistakes were made along the way as well when we created the preliminary armrest video. The thumbnail in Figure 5 shows the basic setup of this rejected video. The guitar is the only prop to give meaning to the image. The video slowly plays the tuck of the hinge into each and every one of the slots. (It’s very repetitive, but nicely rendered.) The audience jumps and flies to see the alignment of the device with the guitar, but does not learn why and only a little bit about how.

The directors thought this video was beautiful. I think we were dazzled by the ability of the software to make the video production easy and controllable. Surprisingly, our nonguitarist friends in the focus group were not interested in watching a boring training video twice, let alone all the way through once.

Poser as a Prop

The props used to present the product are an important part of the design process. We don’t offr the CAD of this guitar accessory; Johnson’s models are proprietary. But we can offer downloadable models we used for the mannequin.

We found that animating the poser so that he seemed to be using the product was a valuable trick. Unfortunately, the free online download from 3dcontentcentral was not ready to use for moviemaking. We wanted to use mouse-drag to quickly position the mannequin. We got there, but it took some prep work to produce moving mannequins.

Figure 1c
This illustration shows the device supporting a guitar. The context of thigh, leg rest, and guitar is informative. The addition of a spotlight helps emphasize the point of interest.

Our CAD tool, SolidWorks®, includes the Mate Controller, which captures a list of positions for limit mates. These include distance and angle. Figure 6 is a snippet of an animation of the poser made with the Mate Controller. The thumbnail in Figure 6 gives a hint that the poser dances around the screen in the video. He has happy feet.

Why is this exciting? Using the poser as a prop in an assembly gives context. Motion Controller allows the poser to behave in the context of the assembly: He can operate stuff. As a result, a movie can be rendered to record his staged behavior.

Only Lonely CAD

How was the movie created? Here’s our work flow for CAD-software-only animation.

After downloading hombre.sldasm, we added concentric mates to his spherical joints. For a couple of the limb models, we had to use Move Body to locate the pivot center at world origin. It takes just a couple of mouse clicks on each part to add the mates at joints. De la Iglesia’s mannequin does not have many parts. That’s a blessing when repeatedly rendering images.

We positioned his torso at a fixed location relative to the world origin. All other components were limit-mated relative to the torso.

We then added distance mates to his hands and feet (relative to the world coordinate top, right, and front planes). Those limit-distance mates proved easier to control for this project compared to limit-angle mates for limbs.

For extra fun, we added hair to his head by sketching a 3-D line for the outline of his scalp, used that for Split Line, then Surface Offset the to-be-hair surfaces. Last we thickened the offset surface to create body in his coif. Yep, that’s a CAD jockey pun.

From experience and for clothing the poser, we used textures that exported from SolidWorks into Composer. Check out the shoelaces and eyelets on his feet!

After capturing a series of positions with the Mate Controller, we used Motion Study to import the scenes from Mate Controller.

We used Motion Study to add camera positions so hombre.sldasm would move around the screen.

Figure 1d
This image is a zoom-out from Figure 1c. Even though the entire product line is visible, the mannequin is the attention-getter. The unrealistic features of the mannequin made this a rejected effort.

Finally, we exported the AVI animation from Motion Study.

Poser Composer

Using different software for animation, specifically SolidWorks Composer, we created another poser to hit the dance floor. A thumbnail can be seen in Figure 7.

Why is this exciting? Composer and Motion Controller are similar in that both capture positions at moments in time as on a storyboard and then animate the transitions between those views. Composer has clever filters and tools in the timeline editor that make the director’s job easier while refining the storyboard. There are no favorites here, just different tools. SolidWorks is a wonderful tool for invention and manufacturing. Composer is a fine tool for presentation and documentation.

The work flow for composing the dashing poser animation called for exporting hombre.sldasm as hombre.SMG and then opening the SMG with Composer. While in that program, we added child-parent links between foot, shin, thigh, abdomen, and torso (for both feet) and then repeated for hand, forearm, bicep, and torso (for both hands). The last child-parent link added was between head and torso, but that was just coincidence. We may add or remove child-parent links as they are needed. The torso is the parent of four children, kinematically speaking. It is the only kinematic/rigid actor in this project.

The next step in our work flow was to set the pivot location (used for transforming the position of actors during rotation) at the local coordinate system for all actors.

Along the way, we set the kinematic type for each of the actors. We used Pivot for all. Spherical works well for this poser too. When the system is in kinematic drag mode, we can move any limb with the mouse. The chain reaction of position for connected limbs is fairly easy to control.

With the kinematic behavior of the poser ready to go, we captured a series of views showing poser standing, striding, squatting, and sitting. Those views were then dragged onto the storyboard timeline. Camera views were added, and the video was rendered.

For setting up still shots for product illustrations, the use of props can help the audience understand the product value. Animation of the product, and the props, can be instructive and entertaining.

We hope you find Poser.sldasm or hombre.smg to be a useful prop in your kit of tricks. Be sure to check out www.thefabricator.com/page/shop-technology- and-3-d-cad-downloads for hombre’s download link to Composer SMG version and the zipped SolidWorks SLDASM version.

Gerald Davis uses CAD software to design and develop products for his clients at www.glddesigns.com. Please send your questions and comments to dand@thefabri cator.com.

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