We have a mandate called the "TransMagic stated geometric tolerance specification". It reads as follows:
TransMagic stated geometric tolerance specification:
Analytic surfaces are converted to a precision of zero or machine tolerance. This means that where-ever an analytic surface is present, such as a cone, sphere, plane, torus, etc. we will convert it to an analytic surface in TransMagic with an identical surface.
Free-Form Spline Surfaces
For free-form spline surfaces such as NUBs, NURBs, Bezier, etc. the geometry internal to the surface is translated at a precision of 10e-6mm - which is an extremely tight tolerance and also essentially zero. In fact this value, 10e-6mm, is the value that TransMagic considers zero (.000001 = 0).
Trim boundaries are precise to exactly what they are in the original file. Depending on the file, this can be anywhere from .1 mm to zero. TransMagic will translate what-ever is in the CAD file. So if a CAD model is generated at a very loose tolerance (very common in V4), we will simply translate at that tolerance.
Class A Surfaces
For Class A surfaces, this refers to a mathematic curvature continuity of the second derivative (C2) between two surfaces. Meaning that the two surfaces have identical speed, direction and radius of curvature at their boundary. This allows two different surfaces to appear as though they are the same surface when subjected to visual inspection and testing such as light reflection line testing. If the math is present to support C2 continuity or even G2 continuity (geometric continuity of the second derivative), then TransMagic will absolutely support and translate that continuity. Note however, that C2 or even G2 is fairly uncommon except in automotive and aerospace sheet-metal applications. The data weight required to support true C2/G2 is pretty high and these surfaces are typically generated by a dedicated add-on to most CAD systems. Most
continuity math found in the surface boundaries in any given CAD file is C1 or G1 - this is usually the curvature associated with blend radii and lofting/sweeping operations. C1 means that the two surfaces have identical speed and parallel radius of curvature (but not identical). This is a much lighter data representation and yet still looks very pleasing to the eye. In any case as will all math data contained in any format that TransMagic supports - TransMagic will simply support what is represented in the original CAD model.
Some antiquated CAD systems use Bezier surfaces vs. the current industry standard NURBs surfaces, an example being CATIA V4. TransMagic's math engine is based on NURBs and analytics so a conversion must be done between Bezier and NURBs to bring such files into TransMagic and vice versa for files being saved out of TransMagic. There is more than one way to perform this conversion and TransMagic has spent a significant amount of resources developing the mathematic algorithms to perform this conversion to our stated tolerances consistently and reliably. In fact in the case of CATIA V4, TransMagic has numerous CATIA V5 customers who have chosen TransMagic for it's CATIA V4 import into CATIA V5 as TransMagic's conversion is more consistent and reliable than CATIA V5's own CATIA V4 translator. Note also that when an application such as CATIA V4 outputs an IGES file for example they themselves are still performing this conversion and the results are quite literally always sub-standard when compared to TransMagic's mathematic conversion on a native CATIA V4 file.
TransMagic will translate original geometry at the same tolerance as the original geometry. - TransMagic will keep in tact the mathematic definition of Class A surface boundaries when they are present or more precisely, TransMagic supports and will keep in tact the mathematic boundary condition of the original model regardless of it's class. TransMagic includes technology (Full Repair) to actually generate more precise intersections (boundary conditions) but this is and will always be a user's decision to use this technology to do so.