CATIA Automotive Extensions Vehicle ArchitectureCAVA
CAVA ensures the legality of the vehicle architecture, international rules, norms and standards during the entire design process.
“CATIA – Automotive Extensions – Vehicle Architecture” (CAVA) resulted from a joint project by Technia Transcat and the german car manufacturers. International rules, norms and standards are provided during the entire design process – from the concept phase to the homologation. CAVA is a feature-based and associative technology integrated with CATIA V5 and V6 / 3DEXPERIENCE.
Throughout the development stage, new car design must comply with legislation and guidelines in the countries where they are licensed. In a joint venture with German car manufacturers, Technia Transcat has developed a solution to these demands – fully integrated into CATIA V5 and V6 / 3DEXPERIENCE. CAVA is now available throughout the world as a CATIA AddOn product.
The task of complying with international regulations, norms and standards does not only affect OEMs. Approximately 70% of development activity rests increasingly with suppliers. Both, OEMs and supplier, will benefit from the CAVA functionality, which simplifies the vehicle concept tasks dramatically. By integrating the CAVA elements tightly inside the feature based architecture of CATIA, they can also be applied across the whole development process, even with international data exchange. CAVA products offer the user new CATIA CAVA features via intuitive menu operations, which correspond to the CATIA feature in terms of handling. These features display the requisite standards information geometrically within CATIA and are saved on CATPart levels. The feature-based architecture also includes associative architecture, i.e. changes in data input prompt an update of the CAVA data. When non-compliance occurs, the user receives the relevant advice. Typical international standards, such as ECE, EEC, FMVSS, SAE, are included but also company-specific standards can be easily incorporated.
CAVA products offer a complete set of easy to use features covering rear view mirror, viewing fields, security belts, underfloor clearances, lamp positions, pedestrian protection, and much more. Each function contains the different values and settings that are determined by local authorities and described in norms like: ECE, EWG, SAE, FMVSS and others. These pre-configured standards are built into CAVA and can easily be administered and extended to company-specific settings.
In general CAVA covers two areas. First, CAVA creates reference or help geometry representing design space, clearance areas, or fields of vision required to support draft and design. Second, since this help geometry is generated from the established standards, any existing or new geometry can be verified against these standards. With these capabilities, CAVA is very useful through the entire development process of a car:
– During the draft phase to provide the boundaries for several design aspects;
– During the entire design to automatically check for legal conformity and report deviations;
– Before homologation to validate that standards have been followed and to create required reports
The CAVA community worked with Technia Transcat to create a standard application that can be used by the OEMs in conjunction with suppliers. CAVA is a certified CAA product, developed with the full support of Dassault Systèmes.
Supply Chain Integration
The CAVA architecture supports the entire process chain including the data created by the embedded supply chain. Through a tight integration to CATIA, CAVA features can be automatically interchanged with the CATIA data so that suppliers and OEMs can use these features throughout the design process.
To use all the CAVA feature functionality, like selecting other laws and standards, modifying current standard values, or creating company-specific rules, a full license is required. To simply use and reference an existing CAVA feature, or to check modified geometry against the established rules, a run-time license is sufficient. Using the “Extract” capability, design spaces can be created to interchange geometry without the CAVA feature intelligence.
At the start of the design process – at the Vehicle Concept phase – usually no detailed geometry for the vehicle is present. The definitive vehicle parameters, such as dimensions, seat positions, etc., are still subject to alteration. In order to create quickly and visually the various (legal) requirements applicable to any current design, CAVA OVA offers a wide range of possibilities.
The OVA “Workbench” provides functions for:
- Static and dynamic curbstone clearances
- Ramp, approach and departure angles
- Total underfloor clearance
- Positions of lights and registration plates
- Bumper height
- Wheel covering
- Seat belt fixing positions and child safety seat systems
CAVA also creates the geometric fields or spaces according to the individual requirements where the components must be positioned – dependent of the current vehicle parameters. When the geometry is added during the development process, it can then be linked to the respective CAVA feature relating to Wheel covering and underfloor clearance functions. The feature indicates directly at the user interface or at the V5 specification tree whether or not the guidelines have been met.
There are a wide range of requirements for vehicle construction with which manufacturers have to comply which relate to the driver’s direct and indirect vision, the latter via the rear view mirror. In CAVA VISION these tasks are covered by a series of different CAVA features.
- Field of View and reference points on the windshield
- Optical properties of the windshield
- A-Pillar obstruction of vision
- Vision Planes
- Direct vision to the front and to the rear
- Calculation of interior and exterior mirrors
The influence geometry has on the driver’s field of vision can be investigated with CAVA Vision in a simple way. Questions such as “Will the vehicle still fulfil the requirements for A-pillar obstruction, if the SgRP (Seating Reference Point) is changed slightly?” are answered in a few clicks.
Legal conformity checks are especially helpful with regard to rear view mirror function, as it is possible to test the impact of specific parameters directly in CAD.
What happens when convex or aspherical glass is used instead of planar glass?
How is the field of vision affected when the radius of the glass is changed?
These are just a few of the possibilities. From this, obstruction of the field of vision due to vehicle design can easily be calculated.
Moreover the functionality of the CAVA Mirror feature has already been approved by different homologation authorities for the European standards.
The direct safety of passengers and pedestrians plays an increasingly major role in the development of new vehicles. It is also approved by some “crash tests” on the real vehicle, based on regulations which are still relatively new. It is important for the designer to identify as early as possible within the CAD System those areas which have to be checked by means of crash tests. With regard to the protection of pedestrians, these include the bonnet and the windscreen, and certain areas in the interior of the vehicle in the case of head impact. The size and position on these areas depends on the vehicle parameters but also on the vehicle geometry in particular.
CAVA Safety provides the user with CAVA features, which calculate these areas and create these as CAVA geometry within CATIA. This informs the constructor of the critical areas early on in the process.
As with all CAVA features, there is a link to the vehicle data, so that the data is (automatically) updated with some modifications.
- Pedestrian protection
- Calculation of required areas on engine hood (flexible tape)
- Calculation of reference curves on bumper and fender
- Head Impact
- Calculation of reference target points inside the car
- Safety Radius
- Check for minimal curvature radius of the exterior design
- Calculation of the specific requirements for the bumper
- Interactive, dynamic calculation by mouse pointer
- Specific handling for grille / lamp elements
- Minimum Radius
- Checking of the minimum radius of the internal vehicle geometry ac
Within the sphere of ergonomics, SAE Standards specify a two-dimensional test dummy, for use in determining the various passenger positions. The dummy can be positioned according to the many different options relating to the geometric guidelines or specifications for the angle of the body and relevant parameters.
Using the contours of the head position and the eye view points and ellipses, all the relevant SAE parameters, such as e.g. headroom or legroom, can be verified. Positioning is also possible across or against the direction of travel.
Generally speaking, the application is used – analogue in the case of OVA – very early on at the concept stage and is completed during the course of development.
- SAE 2D Manikin Template
- Different percentage sizes
- Comfortable positioning
- Check for geomtry clash
- Floor, pedal, angles, hip
- Positioning for rear passengers
- Head Position Contour
- Clearance in vertical and diagonal direction
- Eye points / ellipses
- SRP location curves (SAE)
The geometry of the windshield wipers is not as such subject to legislation, however the area to be wiped must fulfil certain standards. With CAVA Wiper the user can simulate the geometry of the wipers and so determine the wiped area on the windscreen. Used together with the Field of View feature in CAVA Vision, it is possible to check the percentage of wiped area within the field of view.
Up to three wipers can be simulated within one feature here. As well as standard wipers, trapezium wipers and contra directional wipers can also be accommodated. The calculation also provides information regarding the position of the wiper blade to the windscreen and can therefore be used to determine the quality of the wiper operation.
CAVA Tools is a collection CAVA functions just available in the CAVA All bundle but in none of the single products.
Transcat Software offers CAVA Tools to make CAVA technology available to none-automotive customers and to offer more functionalities too those customers using just specific CAVA products.
Currently available in CAVA Tools:
CAVA Silhouette – 2D Projection of geometry outlines
The Silhouette function is offering the possibility to project the silhouette of any selected geometry to a target plane. Thus, helping to create homologation drawings and the frontal area of the car for a drag coefficient calculation.
The Silhouette function is also suitable for applications beyond car design – coming in handy whenever generating a projection of multiple geometry or CGR elements becomes necessary.
- Easy projection of the front area
- Can also be used for other objects (e.g. front printing forms)
- No CAVA data collection necessary
- Supports CATIA CGR and geometric data
- Oriented towards CATIA geometry