Automotive designer using Proe design exterior components need help.

[texaspete]

I am designing some exterior car parts and I need some help. I am working in Millimeters and I am designing exterior lights (head lights, tail tails, reflex, etc). It's back to the age old question about Absolute accuracy vs relative accuracy. What are other automotive suppliers using - relative accuracy and what value are they using, if they are using absolute accuracy what value are you using. Remember I am designing in car position so my geometry is very far from 0,0,0. Could some one inlighten me. ex. I offset a curve (a tangent of a fillet) 7.000 mm and when I use the measure command I get values like 6.98777 . I know that the difference is in the micron but when I am before my customers they say - "that not 7"
Thanks for all who reply.
Texaspete.

 

[Heckler]

This came up when I searched PTC's website for absolute accuracy vs relative accuracy.

Problem models. Be prepared for models that could pose import problems -- this one-in-ten business isn't a random occurrence. The more complex a model, the more prone it is to having a problem. Also, parts that have lots of rounded or sculpted surfaces are trickier than prismatic parts.

Another issue that affects model import is accuracy -- not how accurate the model is but which accuracy mode you're using: absolute or relative. Pro/ENGINEER uses relative accuracy natively, but you can force it to use a fixed absolute accuracy if the model you're importing uses that mode. By switching to absolute mode, you'll have an improved transfer and an easier time merging parts that have the same absolute accuracy. However, you may also have compatibility issues with other parts as you increase the fineness of detail, and both absolute mode and increasing accuracy levels limit Pro/ENGINEER performance.

Also be on the lookout for solid models that don't include topology data. Pro/ENGINEER models contain a part's geometry as well as its topology, or how the surfaces connect to form a closed body. Some systems, particularly older ones, don't support topology when they build or export models. Models imported from these systems are also potential stinkers because without the topology to "glue" the model together, Pro/ENGINEER has to make educated guesses about how the pieces of the puzzle fit.

The one in ten. If a model successfully closes after import, you'll know right away because Pro/ENGINEER will default to wireframe mode and display the model in white. If it doesn't close, the model will be magenta with the broken edges outlined in yellow. Surface problems include missing surfaces, overlapping surfaces, surface singularities, and twisted surfaces; edge/vertex problems include gaps, overlap, tangency, "ripping," and missing bounding edges.

You can fix these flaws using manual tools, an automated tool, or a combination of both.

Manual repair tools let users fix vertices, zip gaps, fix tangency, edit boundaries, and modify surfaces in an interactive manner by manipulating individual edges and surfaces. In the hands of an expert, these are very powerful tools, but you'll have to invest a good chunk of time to learn and use them.

Import Data Doctor automates many of the manual tools for surface cleanup of imported data, and you don't have to be an experienced user to get good results. Based on user input, the system automatically reconstructs the underlying wireframe of the imported geometry, closes gaps, aligns vertices, and rebuilds boundaries. And because it takes into account not only the edges you want to sew together but also the effect of changes on the surrounding surfaces, Import Data Doctor doesn't create new problems while fixing existing ones.

You can run the tool globally or, more effectively, isolate problem areas. A preview feature lets you reject undesirable changes before computation, and after computation the tool delivers feedback on what has changed.

Melding repairs. When you import a model, it may have areas that are so mathematically corrupt or small or invalid that you end up with a hole. Import Data Doctor's Collapse Geometry feature collapses the surface patches you created to close the hole into the import features, making the repairs part of the imported geometry.

The amount of time you'll save using Import Data Doctor instead of futzing with manual tools partially depends on your manual tool skill level. Novice users may save 50 to 60%.

But Import Data Doctor can't do everything. For example, it doesn't let users edit boundaries, fix large holes, pull boundaries, or add and subtract holes to and from surfaces. Experienced manual tool users can take advantage of Import Data Doctor to automate tedious and repetitive repair tasks, then use manual tools for the tough parts to get a model suitable for even the most rigorous downstream applications.


Best Regards,

Heckler

Do you trust your intuition or go with the flow?

 

[HDS]

How are you offsetting the curve? Is it along the surface or in a plane? The difference maybe because you are measuring the shortest distance but you moved it along the surface.