Product Overview

An ultra-fast, oct-tree accelerated Monte-Carlo ray tracing algorithm is used by RadCAD to compute radiation exchange factors and view factors. Innovations by C&R Technologies to the ray tracing process have resulted in an extremely efficient radiation analyzer. A unique progressive radiosity algorithm has also been incorporated to compute radiation exchange factors from view factor data. RadCAD has also incorporated the progressive radiosity algorithm into heating rate calculations, resulting in even faster performance. Automatic compression and decompression of internal database files minimizes disk usage.

RadCAD uses Monte Carlo Ray Tracing to calculate form factors, radiation conductors, and heating rates for true conic surface representations for input into SINDA/FLUINT. RadCAD is the first radiation analyzer to integrate arbitrary CAD generated surfaces with familiar parameter-based (TRASYS like) surfaces.

Enhanced Productivity

Analysis Groups

One of the many powerful concepts in RadCAD is that of a radiation analysis group. Any surface, along with active side designations, can be listed any number of times in different analysis groups. When a radiation computation (form factors, RADKs, or fluxes) is invoked, it operates only on the currently active analysis group.

This provides for speed savings and convenient manipulations of the model. For example, consider the simple model depicted here. The radiation on the inside of the box could be assigned to analysis group "internal," while the same surfaces (with different active sides) could be assigned to the analysis group "external." This permits two faster analyses to be performed, rather than solving the combined case or having to maintain two separate models.

Analysis groups have other uses as well. For example, they enable the user to maintain alternate cases and alternate components within the same geometric model. They are also one of the bases for creating selection sets for model verification and for post processing.

Articulated Geometry

Articulators are modeling objects that can be used to change the position or model geometry. Thermal Desktop has two types of articulators: assemblies and trackers. Assemblies can translate and rotate modeling objects (including other articulators) or groups of modeling objects. The translation and rotation of an assembly is user defined, but can be defined using complex mathematical expressions. Trackers are a special type of articulator that rotates model objects based on relative position, perhaps relative to the Sun or a star. Trackers are useful for pointing solar arrays, thermal radiators, etc. Trackers have a single degree of freedom, but can be nested within other trackers and/or assemblies for unlimited degrees of freedom.

Property Databases and Aliases

Surface optical properties (solar absorptivity, infrared emissivity, degree of specularity, etc.) can be input as numbers, or indirectly as user-defined names ("white paint," "aft canister," etc.). These names can refer to a property identified in a user-controlled database, or they can refer to an alias. Property aliases enable the user to reassign coatings or materials at a high level with little work. For example, using the alias manager as shown here, the user can reassign the optical properties of all components designated "radiator" to be "white paint."

Together with an ability to quickly swap databases (i.e., to change the definition of "white paint" with alternate white paints), aliases provide the user with a quick means of performing what-if analyses, comparing designs, events, and levels of degradation.

Correspondence Trees

Another Thermal Desktop innovation is a tree-style manager for handling the optional correspondence (mapping) between Thermal Desktop surfaces and SINDA nodes. (Correspondence data may be used to collect predictions for one or more nodes together before being output for SINDA.) This intuitive form (as shown here) provides fast visual access to this data, which is difficult to maintain in older analyzers. Correspondence is also automatically maintained when postprocessing SINDA results on the Thermal Desktop drawing (an example of which is shown on the first page).

Cumulative Accuracy

RadCAD allows users to accumulate accuracy by choosing to extend a ray tracing analysis farther after having viewed intermediate results. Previous RADK or heating rate solutions may be continued for added accuracy without losing prior answers. The code automatically checks to make sure that no changes have been made that render the previous analysis invalid as a starting point

Importing/Exporting

As an aid to existing TRASYS users, Thermal Desktop can directly import/export TRASYS geometry and property information (such as the model shown here), retaining a knowledge of BCS organization on different layers, and which can be used as selection sets to help a user better exploit unique new Thermal Desktop features. Thermal Desktop can also import NEVADA and TSS models.

More Information

• Refraction example showing converging lens
• TRASYS comparison document
• Introduction to Thermal Desktop
• Browse Autodesk's Web site

 

RadCAD Features

• CAD drawing methods and high-level RadCAD surfaces including snap-on methods that use CAD drawings as "scaffolding"
• Variable geometry through the use of articulators (assemblies and trackers)
• Solve for form factors, radiation exchange factors, or absorbed fluxes
• Choice of solution methods: accelerated Monte Carlo ray tracing (MCRT) or progressive radiosity
• Proprietary advances in Oct Cell technology for amazingly fast computations
• True curved geometric surfaces
• Specular and Diffuse surfaces
• Angular dependent surface properties
• Full orbital plotting package with both basic and Keplerian input
• Analysis groups offer significant speed savings
• Optical Property Aliases help in database management
• Refraction capabilities for transparent specular surfaces
• Automatic Oct Cell optimization for determining best subdivision and surfaces per cell criteria
• Vector List Orbit definition for modeling trajectory orbits
• Arbitrary source input for modeling IR/Sol Lamps
• Fast spinning surfaces
• Symmetry/Mirror planes
• Automatic restart determination
• Free Molecular Heating (FMH) algorithms
• Quick checks to allow for finding surfaces that overlap to aid in radiation model debugging
• Postprocessing (view factors, RADKs, fluxes, SINDA temperatures, etc.)

Import and Export Capabilities

• TRASYS import and export
• Nevada import
• STEP-TAS import and export
• IDEAS FD import
• TSS import and export

 

Minimum System Requirements

• XP Pro (SP2 or newer), Vista Pro or Home, Windows 7

• AutoCAD
  • 32 Bit Version: 2007, 2008, 2009, 2010 or 2011
  • 64 Bit Version: AutoCAD 2008, 2009, 2010 or 2011

• Memory: 1 GB Minimum for XP, 2 GB for Vista or Windows 7

• Display resolution: 1024x768 minimum, 1280x1024 or finer recommended