Curves and Surface Models - the good, the bad, the ugly

[ptc-6105405]

Hi designers,

I have a report to report about the different curve and surface models used in CAD, specifically Creo. I was wondering what degree of freedom they give designers? Also what is good about using them and what is not/what is frustrating?

Thanks in advance,

stressed uni student

[Patriot_1776]

The question is ambiguous. More detail will help. What are you trying to do?

[ptc-6105405]

Sorry but the topic is an open topic so we just have to talk about curves and surface and the freedom they give designers in creo. I was just wondering what peoples thoughts and experiences are

[Dale_Rosema]

Sorry, in a goofing mood:

We should have free range curves. No fences, no boundaries. Let them go where ever they want to go.

Again, I am not sure your topic is refined enough. Are you talking about using surface models and solidify versus extruding solids?

[dschenken]

It's like taking a whack at a doctorate-level mathematics-filled pinata.

Fortunately most of the formulaic goodness has a tasty GUI coating to contain most of the sweet interior (I'm looking at you Bezier functions,) but that's true of all CAD programs. More specifically, one can create curves and surfaces that are sufficiently accurate in representing realizable real-world items. Whether one considers it difficult to do so depends on training and imagination.

I am a bit disappointed the web-site spell checker doesn't like Bezier and has no adequate suggestion.

[TomD.inPDX]

You have to remember that PTC has an optional extension for higher quality surface generation for more stylistic solution. This "optional" product nature doesn't sit right with me. The evolution of the product should include enhancements... not just pretty.. and useless ribbons. Otherwise my maintenance dollars are simply going to other offerings I can never afford... because I am paying maintenance.

Curves are fairly straight forward. We have many ways to generate curve paths and even surface edges work for trajectories. In general, curves are only useful for construction purposes. They always get in the way when making drawings if you forget to hide them well in layers.

What I find troubling is the absolutely archaic drawing sketch tools. YUCK!

[Patriot_1776]

I use curves and surfaces extensively. You can create curves from an equation based on a coordinate system (IMPO the single most powerful feature), based on the intersection of 2 sketched curves (my favorite for routing tubing and cable), the intersection of 2 surfaces, using edges of surfaces and solids, thru a series of points (with tangency or normal constraints available on both ends), wrapped around or projected onto surfaces, or simply sketched in 2D.

Surfaces are great for complicated shapes you can't do with simple extrudes or other solid features, to be used to extrude protrusions or cuts to, to use the edges of for trajectories (one of my favorite uses), for cosmetic details.

Really, almost the only limitation is the user. They can be REALLY powerful tools for the expert.