TurboCAD v10.5

Mauritz Botha of IMSI spent a few minutes last week showing me the features new to TurboCAD v10.5. Primarily, it's the addition of a constraint manager (licensed from D-Cubed, a group of brillian British mathematicians who come up with most of the features found in competing mechanical CAD packages.)

Constraints perform two tasks:

* Define how object connect to each other.
* Drive dimensions.

Constraints are not new technology. Bentley Systems added them to MicroStation a decade ago. Today, the technology is found primarily in MCAD systems.

Constraints

The drawback to constraints is that it takes advance planning to implement: which objects are supposed to connect, and how do they connect? After all, TurboCAD includes more than a dozen constraints for 2D and 3D objects:

- point
- connection
- parallel
- perpendicular
- tangent
- concentric
- symmetric
- equal radius
- equal length
- equal distance
- change chirality
- fix geometry

Take the Concentric constraint, for example. A hole is constrained by an adjacent fillet: make the fillet smaller, and the hole reduces size.

To assist in the second half of the question, TurboCAD includes AutoConstraint. Select an object, and a toolbar lists the constraints that apply to it. Toggle off the constraints you don't want. Mr Botha says this tool is excellent for bringing in drawings from other CAD packages, such as AutoCAD (which lacks constraint management) and then quickly applying constraints.

After constraint(s) are applied, icons appear signalling the type of constraint. These can, naturally, be toggled off to de-crowd the drawing. Right-click the constraint icon, and affected objects are highlighted.

As for chirality, that's a term new to us in CAD, but common in molecular chemisty -- it means "handedness" refers to structures can be mirror images, like your left and right hands. In the context of constraints, it refers to how, say, an arc connects to a line. The arc could connect facing two different ways, convex or concave.

Driving Driven Dimensions

Constraints are also involved with dimensions. These dimensions can consist of distances (like regular dimensions) or consist of forumlas. The formulas are often based on the position and size of other objects. So, dimensions change the size of objects, depending on how other objects change.

The figure shows dimensions driving objects; formulae are seen in the panel on the right. (Click thumbnail for larger image.)

Who uses constraints? I asked Mr Botha. Primarily those TurboCAD customers involved in mechanical CAD designs and even more so in CAM [computer-aided machining]. V10.5 beta testers didn't know what to do with constraints until IMSI provided them with some sample drawings, at which point the light went on.

Comments

[Tony Tanzillo]

In your comments on TurboCAD 10.5's constraints, you wrote:

"Constraints - The drawback to constraints is that it takes advance planning to implement: which objects are supposed to connect, and how do they connect? "

This is not really the case. Constraints can be defined explicitly, or 'derived' by inference. For example, when you draw a line and object snap one of its endpoints to the end of another line, the software can recognize that 'implied' relationship, and define a constraint for you, on the fly, as you draw.

In fact, that's exactly how the feature (known as 'Relationships') in Intergraph's SmartSketch works - It watches what the user does and defines constraints for them on the fly, based on the implied relationships inferred by various actions (such as connecting the end of a line to another line, or drawing a line parallel or perpenducular to another line, and so on).

Unfortunately for AutoCAD users, while DCubed constraint management technology has been around in various incarnations for well over ten years in products costing the same as AutoCAD LT, AutoCAD still to this day, lacks any form of generic, constraint-based functionality.

[Mike Young]

How do you turn on the top tab line in TurboCAD 11?

Such as standar, line, ARC, Dimension, Text, #D, Modify, Cpy, Constraints, Properties

Mike@firehouseinternational.com

Thank You