Issue #1,120 | Inside the Business of CAD | 31 January 2022
Guest editorial by Ivan Rykov
Plug-in adding a toolbar and a panel to Rhino
Many projects developed by LEDAS are plug-ins for CAD software programs, ranging from powerful systems like CATIA, to lighter weight solutions like Rhino. Oftimes, we help our customers decide on the direction in which their ideas are best developed: in the form of a plug-in or as a standalone program.
Pros and Cons of Plug-ins
Plug-ins either solve specific problems, or else add functions missing from CAD systems. A good example is CAMWorks from HCL, an advanced plug-in that adds computer-aided manufacturing functions to the Solidworks MCAD system.
Comparing plug-ins with independent applications, we found that plug-ins are better suited to software used in-house by design engineers, with the aim of assisting their day-to-day work. In certain cases, the plug-in approach significantly reduces the cost of development. Ready-made CAD systems work with plug-ins through their APIs [application programming interface].
The drawback to plug-ins that you have to run them on a host application. Before the plug-in can be used, you have to pay a license fee and then install the host software. Plug-ins intended for wider distribution have their demand limited by the number of seats found of the target CAD system.
The APIs provided by CAD systems are often thought of as a way to extend and tailor functions of the CAD system itself, rather than for creating customized processes to solve particular problems. Also, it’s not always an easy task to make a focused plug-in which overrides the user interface of the host application to substitute its own workflow.
We have found that, in general, end-user plug-ins are not usually at the top of our customers’ wish lists.
Pros and Cons of Standalone Applications
More commonly, our customers want software made as standalone programs for the desktop and, more often in recent years, a client-server Web application.
When considering the development of an independent application, either for desktop or the Web, keep in mind that it will require a geometric kernel with which it constructs, represents, and tessellates 3D objects. (We talk more about kernels on our 3D Modeling page.) The annual cost of a subscription license for a kernel is usually significantly higher than a one-time payment for a single license of a lightweight or middle-class CAD system on which plug-ins can run.
Another source of cost is the effort to implement 3D scenes: visualization, camera manipulation (zoom, pan, rotate), object manipulation (selection, movements), and so on. With a plug-in, the host application provides all these features via its API. In case of standalone applications, these have to be programmed at a low level, or else with the help of licensed visualization components.
Types of Plug-in Solutions
From our experience, Rhino is an excellent example of a customizable system. It allows us to hide most of its default panels and toolbars, and then we can easily create our own panels using WPF [Windows Presentation Foundation]. This gives us almost the level of same control over the Rhino’s user interface as do independent WPF applications. (See figure at the top of this article.)
In other CAD systems, this could become problematic as they might use outdated GUI frameworks (do you recall WxWidgets?) or are limited to UI controls predefined by their APIs.
If, however, the application has an external API that can be called from another process, such as through COM or WCF, then we can build a plug-in UI as an external application that interacts with the host CAD system through the API. (Technically, this is then not strictly considered a plug-in.)
This allows us to build the UI using modern technologies exactly matching the required processes, yet still using the geometric kernel and 3D scene capabilities of the host CAD application. This approach is quite popular with our customers, although a somewhat more complicated approach.
How to Decide
So, we have trade-offs that can be resolved by knowing the number of simultaneous software users:
When the cost of copies of the host CAD system does not exceed the cost of a custom application (with licenses for geometric kernel, visualization components, and 3D scene implementation), a plug-in is the cheaper option.
It’s worth noting that the cost of licensing the host application can at times be considered to be zero when company engineers are already using the software in their daily work. In this case, a plug-in based on such a system possesses the additional benefit of fitting a familiar environment.
Thus, in our experience, plug-in solutions are quite popular for semi-automation of certain CAD-related processes performed by a small group of engineers, or else by a large group already using a suitable CAD system. Many of our digital medicine projects, for example, are in the form of plug-ins.
[Ivan Rykov is chief technology officer at LEDAS since 2004. Dr Rykov graduated from the mechanics and mathematics department of Novosibirsk State University, and in 2009 received his PhD in physics and mathematics specializing in discrete mathematics and mathematical cybernetics. More at ledas.com/en.]
Project Newplex 2.0 is the advanced SHX font designed for technical documents; compatible with every DWG-based CAD program that supports Unicode SHX files.
Features
Advanced character forms for readability & clarity
Autodesk launches Flex, its token-based pay-as-you-go system for renting software by the day. AutoCAD, for instance, costs 7 tokens (US$21) for 24 hours, which can be paused by closing the application. Netfab Ultimate, at 55 tokens daily, is the most expensive.
For the very intermittent user, like me, this would be a useful duration, but, alas, I cannot buy a day’s worth, because the minimum purchase is 500 tokens that last just one year, and costs just C$365 less than an annual subscription. Maybe that’s the point. Autodesk warns that “daily rates are subject to change,” meaning the cost/token could rise at any time. autodesk.com/benefits/flex/estimator-tool
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OpenDesign Alliance initiates development of a scan-to-BIM software development kit. Or more accurately: laser scans > polygonal surfaces > AEC objects (b-reps) > parametric parts classified in IFC, Revit, and other formats.
To join the dozen other firms working on it, you first have to become a SIG member at $20,000/year; details at https://opendesign.com/scan-to-bim.
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Here are some of the posts that appeared recently on my WorldCAD Access blog:
While experiencing the same problem with my Logitech M185 and reading through suggestions [on WorldCAD Access], I took a hint from a very old post that referenced the jumpy problem on an old mouse with a rubber ball. It suggested cleaning the ball and inside the mouse.
My newer M185 did not have a ball, but rather a movement sensor window. I took a Q-tip and cleaned the little window on the underside of the mouse, [see figure above] and the problem disappeared. - Roger Carlsen (via WorldCAD Access)
Re: Which Comes First: Models or Drawings?
The usefulness of either a model or a drawing depends, in part, on what you are using it for. If you are a developer, a rough hand sketch might do fine. If you are an estimator you may be able to get by with fewer details (and less accuracy, whatever that means) than if you are trying to build a building.
Two issues run throughout a real-life examination of models and drawings:
1. Knowledge. Does the creator have the knowledge necessary to create the desired level of detail? In construction it is ridiculously impossible for an architect to have the requisite knowledge for the final design of every component in a building. The less knowledge implicitly contained in a drawing or model, the less useful it is. Each type of use requires a different amount of knowledge to implicitly dwell within the model.
2. Responsibility. Who is legally required to get it right? In USA, architects, who most typically create a model, have a low bar for liability for the design; that is pushed contractually to general contractors and from there to subcontractors.
Subs cannot stay viable in the business without serious knowledge; the others can shrug off any liability for not getting a design quite right. - Leo Schlosberg
The editor replies: Back in the day when I designed traffic signal installations, we used symbols like the ones shown below, which contractors interpreted.
“The experts predicted the future, but nature had other ideas.” - Richard Fernandez (@wretchardthecat)
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