Alias cvs

Does anyone know:
When pulling cv points in alias , is there a way to set the “influence” of a point so it pulls the surrounding ones as well? (It would be nice when pulling small details in a big surface)

I’m pretty sure you can’t do what you’re asking about, but if you post a pic or a more detailed explanation of what you’re trying to build, I’ll try to help you out…

You could try moving hulls instead of cvs. This allows you to pick lines of cvs instead of individuals.

I don’t know of a way to “blend” the effect so that neighboring cvs or hulls are pulled along, but move less as they get farther away from the initial cv/hull, but perhaps it is possible. I’ve seen such a tool in Wildfire 2.

Posting an image is a good idea. There may be another way to model the feature.

Transform > Modify > Proportional mod

The “degree” parameter defines the degree of influence; the “preceding” and “succeding” parameters define the number of CVs influenced.

The Move CV tool found in the Control Panel displays a large arrow in “slide” mode when hulls or a complete line or CVs is selected that just does this as well.

Nice, that’s pretty crazy. The depth of this program never ceases to amaze me…

and now, for something completely different:

Adjust weight

it’s buried somewhere in the palette, i think in the Curve Edit tab.

it allows you to slide left and right to increase or decrease the specific influence of the selected vertices relative to the unselected ones. i know, this isn’t what you wanted, but it is in a similar vein, and it is fun to use for conceptual work.

note that this is a net sum zero game, as in picking all cv’s in a curve or surface and adusting the weight will yield no change. so you have to adjust at least one less than all the verts in a curve or surf in order to see some change. start with a single span degree three curve with some amount of curvature > 0, as in not a straight line, and Adjust Weight on one cv.

why is this not so worthwhile? cause iges doesn’t respect the adjusted weight of specific cv’s unless you flag the rebuild on when you export to iges, and we all know how useful that is… not.

anyway, another method is to select a set of cv’s and snap the pivot to some nearby cv, perhaps a central one, or even use Center Pivot, then nonp scale. this allows you to influence many points at once in a controlled, predictable fashion. you can soften a bump in a patch this way.

wow thanks guys, I think dacct’s one sounds like the closest thing to what i’m looking for, i’ll give it a try.
As for the pix, i’m a bit bad with posting images, but imagine a flat surf. and bumps go down in random spots, but pretty close together, so i can’t use a small amount of cvs, I actually end up with a pretty busy mesh of cvs, which i then have to control to make the bumps smooth.

It works like a charm, that’s what I needed, thanks a lot
: )

It is really not advisable to play with the weights of Cvs to obtain shape. Doing that converts the curve into a rational one. Subsequent use of the rational curve in surfacing operations can cause the complexity of the data to snowball.

In theory, there is nothing wrong with playing with the weights of CVs but in practicality, it is really not an advisable workflow - especially if the data needs to be taken further in your modelling process.

Use with caution, that is…

There are countless other ways of modifying the shape of curves or creating curves of required shape in Alias. I would advice you to explore those…


well, okay, don’t use adjust weight. i wasn’t saying use it all the time, but it is nice to be able to occasionally sculpt surfaces in subtle ways without adding extra cv’s. like i said, you’d have to rebuild before sending downstream to another app so it has limited usefulness, but i think the tool is useful. in this thread, though, prop mod is much more applicable.