@unknownuser said:

Maybe this can help you (click image for zoom)

Ah. it's the "hit Enter TWICE" thing. also, I made the newbie error of clicking in the small text entry box at lower right, which isn't necessary and actually seems to mess things up. I've just managed to get the tool to work and WOW. very nice animation. I enjoyed making my bubble "breathe" by fooling with the pressure values.

now all of a sudden I'm having FEA dreams -- modulus of elasticity of various materials, and a realistic response to pressure. [just kidding, just kidding] thank you Pilou.

@gaieus said:

Hi De Clarke and Simon, both welcome.

DC: there are numerous newer plugins that do a better job than skin.rb (which was a very nice plugin at its time but the author seems to have abandoned the project).

Look at Cris Fullmer's loft tool now for instance.

Thank you Gaieus -- the only hit I got for the loft tool was an alpha release back in May -- is that the one? it looks rather hopeful. My learning curve is nearly vertical at this point, so I hope everyone will forgive the inevitable newbie idiocies. I've become a little obsessed with SU -- watched all the official Google minivids and walked through all the self-paced skp tuts, and am now in the "collecting really kewl plugins" phase. I'm still trying to get that "feel" for how to approach the modelling of an object in the way that is natural and easy with SU, rather than doing things all bassackwards. skp tuts are absolutely wonderful, I have never seen a software tool before that so easily and perfectly provides its own HOWTO. the "assembly line" walk-through skp's used by some of the boat hull modellers are wonderful.

I've written quite a few data viz interfaces in my time, and so I've got my hat off in sincere admiration for the thought and creativity that went into the SU local universe. the rules are remarkably consistent and the core method/approach to simple models (subtractive and additive extrusion) is very powerful. we've come a long way since paper tape readers (and yes, I remember them personally).

I gave Screw 2.3 a try but so far am puzzled by it. This version does not offer an entry box for the offset, just a step count and number of turns. I am always getting zero offset -- it just "smears" the shape around into a torus.

I had a look at the source code and though I don't speak Ruby, I got the impression that it was somehow inferring the offset from the geometry of the shape to be smeared -- some kind of slope derived from an edge orthogonal to the axis of the lathing operation. Can anyone confirm?

newbie idiot here...

I'm trying to learn how to make curved surfaces with soap/skin plugin...

Is there any tutorial skp for this plugin? so far I cannot even figure out where to input the parameters... they display at upper R of screen but do not appear to be editable. am I missing some other plugin that would provide a popup form for parameter entry?

can anyone point me to a step-by-step tutorial for using soap/skin?

Just introducing myself.

I am a rank newbie to CAD/CAM (I know what it does, but my day job was in the s'ware engineering, not mech engineering department; the closest I got to AutoCAD was looking over other people's shoulders). Now I'm retired and working on boats for fun and occasional profit, and I am kind of excited about using Sketchup to model boat hulls and interiors -- first project would be modelling the interior of my own boat, in order to visualise various options for a planned remodel.

The catch is of course that boats are all made of weird angles and complex contours -- nothing is parallel or orthogonal and a lot of surfaces have compound curvature -- and curved surfaces seem to be kind of an advanced topic (requiring plugins of various kinds) in Sketchup. [I did get "skin23" plugin but so far have not managed to get it to do anything at all I suspect it may require some other plugin that I don't yet have -- either that or it doesn't like SU7.] I'd sure like to know how the authors made e.g. the sails of the various spiffy boat models I've been looking at. Being able to warp or deform plane surfaces by various (catenary, hyperbolic, parabolic, spherical, etc) algorithms would be very handy.

At any rate, my top priority is to learn how to make flat shapes into complex curves, such as fabric (or sheet steel) under tension; sail forms, hull forms, foils, etc. Any tips or pointers would be most welcome.