skate bowl NURBS

[digitalcarbon]

need some help

http://youtu.be/QKO3JxkvnZ8

thanks

[Gytis]

bad youtube link.

could you pls export back to VW2010 and i'll look.

[digitalcarbon]

first video repasted

http://youtu.be/QKO3JxkvnZ8

if that does not work i will resubmit to youtube

try this http://youtu.be/_vuj_-6WFYw

here is a second attempt on the bowl in vw

http://youtu.be/olxFhtTbXm4

and the second vw file

[michaelk]

Is this closer?

[digitalcarbon]

its better but ti still has wrinkles in it

what did you do different?

[Kevin McAllister]

I suspect there's a way to get closer to what you want. I think the stumbling block is the third mode of the loft surface. Some observations -

- the twisting / wrinkles are most likely caused by a different number of points in the two rail curves. To get a clean result the guideline drawn when running the loft surface command needs to be perpendicular.

- the smaller "radius" is not actually a true radius.

I did a quick experiment which I've attached. I created two bowls using Revolve with Rail (a bottom curve, a top curve and a vertical axis). I then used the Create Fillet Surface to join them. You can see how it wants to correct things to make a nice surface.

My experience with the Loft Surface command is ideally you want to be able to check the ruled surface box as you will get a much cleaner result. I think I would try creating half and then mirroring it or Loft Surface using the first mode (use your existing two curves and creating at least one intermediary).

Kevin

[michaelk]

I agree with Kevin that the wrinkles are caused by a different number of vertices. There are 19 on the bottom and 23 on the top. If you can make them both the same it will loft much more smoothly.

I'm not sure you really need to make the loft ruled. I think you get better curve rendering no ruled.

mk

[digitalcarbon]

Kevin, thanks for the model looks great. but need to make it in one surface because once in get the surface of this whole park then i will shell it to 6 inch thick

the object you made is 3 surfaces i need one

[Kevin McAllister]

I'm not sure that's possible. You can use Stitch and Trim to join some of the surfaces I created (the sides of the bowls to the bottoms for example) but I couldn't get them all to join and then shell.

I think trying to join the entire park into a single surface is going to be quite the challenge if its multiple shapes similar to these.

My experience is that NURBS are almost always in pieces as the surfaces get more complex. And shells are fairly particular themselves.

Kevin

[Benson Shaw]

Little late to the party here, but:

The Bi Rail Sweep can work, but simple Loft Surface of either ribs (probably how it would be built) or horizontal contours produces a better surface and shell.

DM's bottom curve is discontinuous and has an inconvenient start/end, both of which cause problems. The ramp ends btw little bowl and big bowl are sharp corners (also the start/end of the NURBS curve). Skaters would probably prefer a tangent fillet. The Loft tool definitely prefers tangency to discontinuity.

After adjusting the bottom curveI, I got the birail to work with only minor deviation, but result was a group of 19 NURBS surfaces. It shells OK.

Lofting ribs created a single surface, but setting up the ribs took some effort. With real data or parameters for the ribs & fillets, the loft could be perfect.

Combining the entire park into a single surface/shell seems unrealistic and unnecessary. It would be built as components anyway - bowls, slabs with joints, etc.

-B

Here are some images:

Edited August 1, 2013 by Benson Shaw

[mike m oz]

Thank you Benson for your very helpful and informative post.

[digitalcarbon]

Benson, your awesome!

[digitalcarbon]

the only reason i want to have skate park all one unit is that after i do all my angles i then use the Fillet Edge Tool to round all my corners. then when i shell i have the radius on the bottom of the concrete also.. not sure how i would chop this up. take a look

[Benson Shaw]

DM - It seems you are starting with the flat faces, then filleting? So you already have it divided? I don't use the fillet tool much, mainly because editing is kind of funky. I usually model with various forms of lofts or EAPs - good for tapered fillets, too. But it looks like your method is working, so go for it! Will you modeling drain slopes, too?

Are you consulting some skaters for best fun factor and challenges? I have heard skaters around here criticize some of the parks as poorly designed or constructed. They also love some of the skateparks. Mainly they just wish there were more of them.

DM & Mike - thanks for the compliments. I hope the ideas are helpful!

-B

[Kevin McAllister]

Benson, I have to agree with DM and Mike, your instructions are pretty great. I find that NURBS can be fairly intuitive if you work with them a lot, but there isn't great information in the manual so there is a lot of trial and error while you're learning.

Kevin

[Benson Shaw]

I'm a total nut for NURBS. One problem I have is learning something, then not using it for a while (years?) and having to rediscover. The happy side is that the software actually improves, despite gripes and whines from techboard denizens, with many things getting easier to learn and use over time. OK, some other things don't improve, and Help isn't always helpful. But I'mstaying hopeful.

-B

[digitalcarbon]

hello Benson, the park shown is design 3 now on design 6. and it is just a proposal to see if town is interested.

also, im a pretty good skater myself

even better at the ramps

[Gytis]

That's impressive DM. Quite humble of you to make the vids public.

I'm gimping about with a broken ankle from downhill mountain biking. Maybe I should post some heroic vids too. :grin:

[digitalcarbon]

yikes broken ankle. i think i will stay away from mountain biking.

honestly, the crashed are more fun to watch

[Benson Shaw]

Excellent, DM!

Great wipeouts! I feel your pain. The only time I ever broke one of my bones was getting off a skateboard - the steel wheel kind. Moved up to the walnut shell & resin wheels shortly thereafter. This in the Rocky Mt foothills when skateboarding consisted of walking up the hill and rolling down the sidewalk, trying to make the turn at bottom. Well, we nailed together some little jumps, too, but never worked out the fillet. Grinds & ollies unheard of. Sorry, no vids.

-B