Tracing Sketches from image and creating surfaces

Hi everybody Some one can help me?? I'm trying to create a car model with tracing sketches in style mode. Some one have any suggestion to make a better work?? Or a suggest about wich training course i must do to get the know how?? Tanks in advance!!! Regards!!!

How could I have a suggestion for a "better way" if I don't know WTF you're doing!?! PTC has a course on Style features. It's a very good introduction to the fundementals, better than most of their courses.

David Janes

Hi david!! You're right !!! Yes i'm trying to model a car an Audi A3 , with the bitmaps set in planes to trace either the lines. But the question is how can i create good 3d lines , to make up a good surface?? Tanks !!! Bye David!!!

Hi david!! You're right !!! Yes i'm trying to model a car an Audi A3 , with the bitmaps set in planes to trace either the lines. But the question is how can i create good 3d lines , to make up a good surface?? Tanks !!! Bye David!!!

Obviously, I would have preferred hearing what you've done, what worked and what didn't and what problems you've run into. In the absence of said, here's my scatter shot, possibly wide of mark, best guess: 1.. Use high contrast images ~ dark image, light background, sharp edges. You are trying to attach, not to a curve, but a pixel. So, screen resolution might count as well, certainly image resolution does. 2.. The fewer the defining/modifying points, the smoother the curve. The more the points the bumpier the curve. So, as much as possible, with Style curves, control the shape with end point direction and tangency length. Use analysis on surface and curve to see smoothness. 3.. Add points, where necessary, to anchor uncooperative geometry, but only enough to make it behave. More points only makes the bumps smaller by creating MORE bumps. 4.. Model in halves, make point at adjacent plane normal to plane; mirror other half. I know this is very general. I might be able to be more specific with a more specific question. Sorr, no tutorial up my sleeve.

David Janes

Hi david!! You're right !!! Yes i'm trying to model a car an Audi A3 , with the bitmaps set in planes to trace either the lines. But the question is how can i create good 3d lines , to make up a good surface?? Tanks !!! Bye David!!!

One last point I meant to make but forgot: the spline curve you make with ISDX is great for curvature continuous surfaces. But where you are tracing something with an obvious break in continuity, end the curve at the break and start a new one. Don't try to force your spline to create sharp corners or even simple tangencies at radiuses. Use separate curves and set end point tangencies accordingly.

David Janes

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is great for curvature continuous surfaces. But where you are tracing something with an obvious break in continuity, end the curve at the break and start a new one. Don't try to force your spline to create sharp corners or even simple tangencies at radiuses. Use separate curves and set end point tangencies accordingly.

The same thing applies to surfaces. Make separate surfaces if there is a non-tangent connection between them. Also I agree with Dave that the fewer points the better. This applies to datum curves for boundary surfaces also.

Tanks for the time spent!!! Regards Bye

. > Hi david!! > You're right !!! Yes i'm trying to model a car an Audi A3 , with the > bitmaps set in planes to trace either the lines. But the question is how > can i create good 3d lines , to make up a good surface?? > Tanks !!! > Bye David!!!

The same thing applies to surfaces. Make separate surfaces if there is a non-tangent connection between them. Also I agree with Dave that the fewer points the better. This applies to datum curves for boundary surfaces also.

Here's the clincher: on a boundary blend or VSS type surface, the surface will exhibit as many patches as there are breaks or discontinuities in the base curves. So, for example, the left curve of a boundary blend surface has three breaks that are less than optimal (will support less than G2 surface curvature). And the right curve has two segments that are not curvature continuous. Your resulting surface will probably have at least 5 patches, depending on any cross curves involved, which could further segment the surface, requiring further merges and more definitions of continuity in order to form a single quilt.

David Janes

Tanks once again!! Regards

Tanks once again!! Regards

I guess, in the end, what I'd suggest is to make composite curves (Crtl select all segments, shift select contiguous) with ^C {& deselect original} & ^V {left click place new}!

David Janes