RcCad

Jim Dall reviews this hot piece of model design software.

 

Introduction

When I was asked to review RcCad, a computer aided design (CAD) product, for the E-Zone magazine I was skeptical about the potential merits of this low cost program. Having spent many hours using expensive CAD programs, I could not visualize how RcCad could assist me in the design process. This just goes to show how short sighted one can be. The more I used RcCad the more impressed I became. I was amazed with the ease of the editing environment and the ability to see 3 dimensional design changes on the fly.

 

Definitions

Before I delve into the remainder of the article I would like to define some terms I used to avoid any confusion. Although the definitions of these terms are relevant to this article, they should not to be considered the ultimate authority on their meanings!

• Plan Views:   The three primary 2D views- top, side, and front that define a 3D object.
• VRLM:   Virtual Reality Modeling Language. The use of technology results in the same type of 3D viewing supplied in RcCad.
• Electronics:   The term electronics in this article refers to a 3D box that is dimensioned in accordance with any component you would like to define for the airplane. The supplied electronic object definitions are receivers, servos, and accumulators.
• Faired: Two surfaces intersected with a blended radial fillet.
• Non-Faired:  Two surfaces intersected with a sharp well defined angular intersection.

 

RcCad Capabilities

RcCad offers the designer a range of capabilities that are not readily apparent upon first review of the product. The following is a summary of the capabilities I identified during product assessment:

• On the fly 3D morphing of changes to front, side, or top plan views.

• The ability to import bitmap files into a plan view to use as a guide in designing a particular view of the airplane. Using this function one could design an airplane based on three views (top, side, and front) stored in a bitmap file format. RcCad incorporates resize and move tools to fit the imported picture with your drawing

• Smoothing tools incorporated into the associated editing tabs.

• The ability to reshape of the entire plane using an isometric factor (preference panel). This can be useful if you design a 60 inch wingspan plane and then decide to decrease it down to a 50 inch span, maintaining the same proportions.

• The ability to incorporate electronics into the design to ensure fit and placement. There is a standard offering of electronics but equipment outside of this offering can also defined.

• The ability to print full size patterns (top, bottom, side, and defined sections). An experienced builder could build straight off of these printouts. The structural detail would not be included but the overall shape and an outline of the individual sections are provided.

• The ability to save the 2D plan views and associated objects in a DXF format. These views are easily imported into other CAD programs and can be used as the basis for complete detailed drawings.

• The ability to save your 3D model in a VRLM format. This format is used to dynamically evaluate a 3D model using free, readily available, download VRLM viewer applications.

• Multiple fuselage sections can be generated to form additional features on the airplane such as engine cowlings, windscreens, additional fuselages, etc.

• Colors can be assigned to different objects within the airplane making editing and viewing more refined and appealing.

• Three ingenious click and drag editing selection functions: move entire object horizontally within the plan view, move entire object vertically within the plan view, stretch the object at a particular intersection.

 

Environment Basics

RcCad is a design tool that provides a live 3D model of a design instantaneously morphing changes that are made to the plan views. Although this feature is very sophisticated, the methods employed to edit the plan views are extremely simple and efficient. It may not be readily apparent to the first time user, but the "ease of use" can be contributed to several subtle and ingenious editing features like automatic scaling, proportional object placement, and the automatic object selection and editing algorithms. Within the different plan views the elements that are available for edit are displayed with black lines, and the elements that are not available for edit are displayed with blue lines.

To design an airplane, or anything else for that matter, you start with the default glider and edit or add objects to generate the final product. Within RcCad there are five primary types of objects supported: elevator/stabilizer, rudder/fin, wings, fuselages, and accessories/electronics. Each of these five types of objects are supported by tabs. The tabs allow for numeric editing of the key object parameters and also facilitate object smoothing functions. The finished product is saved in an RcCad project file. The significance of this is that you can not reload a project you have saved using the "demo version" without the procured key to enable this option. The "demo version" will not load project files.

 

Fuselage Design Strategy

The fuselage object geometry can be most effectively edited by adding sections and defining the shape of these sections. You can individually define the shape of each section or can change the shape of one section, and RcCad will automatically shape all other sections proportionately. The sections of each individual fuselage object are faired to each other. This provides a smooth and continuous surface. To provide a non-faired feature it is easiest to generate another fuselage object, shape it to simulate the desired feature, and intersect it with the main fuselage object. A fuselage object can be transformed into anything and is by far the most flexible design element in RcCad. Some of the more interesting designs published in the RcCad Web Page Gallery use 20 or more fuselage objects.

 

Elevator/Stabilizer Design Strategy

The elevator/stabilizer are one design element in RcCad. All aspects of these two fins can be edited via click and drag and numeric attribute fields in the associated tab. You can not duplicate this design object or change the basic cord-wise geometry of the element.

 

Rudder/Fin Design Strategy

The rudder/fin are one design element in RcCad. This element is actually comprised of two fins and is displayed on the initial glider side by side so it appears as one object. The editing methodology is the same as on the elevator/stabilizer. You can not duplicate this design object or change the basic cord-wise geometry of the element.

 

Wing Strategy

The wing elements are similar to the fuselage, but allow for one additional panel per wing. These panels can be used for winglets, for polyhedral detail, and for foil tapering. The editing methodology is the same as on the elevator/stabilizer. You can not change the basic cord-wise geometry of these elements.

 

Accessories/Electronics Strategy

The accessories/electronics elements are basically boxes that represent the volume associated with these accessories/electronics: servos, receivers, accumulators, etc. These objects can be moved around the design to optimize their fit and placement. RcCad has a limited inventory of these types of objects but allows you to specify any rectangular representation of an object. RcCad allows you to use many of these accessories/electronic objects in your design. I have not found a limit to the number of these objects you can incorporate into your design.

 

RcCad Software Use and Procurement

The "demo version" of RcCad is available for download at http://www.rccad.com. The "demo version" is actually the complete application with project loading, picture import, and DXF export disabled. The number of fuselages is also limited to 4. All the other features are available without any kind of limitations. The download also includes some samples of DXF exports. To purchases RcCad ($49.95, this offer is limited to orders received before June 30, 1999) a key that references the serial number of your program is provide. The RcCad key/licensed is only good for one machine. This key enables the full version of RcCad with the following:

• Unlimited number of fuselages.
• Load RcCad project function enabled.
• Export to DXF format (still in beta test). Note: This function worked fine for me
• Import of bitmap pictures.
• All the updates released with the number V1.x.x
• The right to resell RcCad.

 

Conclusion

RcCad is an excellent tool to develop and prototype aircraft designs. I am truly amazed at the speed and ease of design offered by the application environment. For me, I found it easier to design from scratch than to replicate an existing design. Although the tools are in place to make replication as easy as possible, the designs I created from scratch looked much better and were far easier to create. Use of this software and associated performance design tools like Motocalc should equip any person, with moderate computer skills and a good imagination, to design truly unique aircraft. I highly suggest a thorough investigation of the RcCad Web Site (http://www.rccad.com) to witness the true potential of this tool and to download a copy for your own evaluation.