Unrolling road

[Kaprolactam]

Hello gang,

I've been lurking for a while and learning a lot from you, but now the time has come for me to ask for your help.

I'm currently trying to animate an unrolling road that is swerving through the landscape. I've already got a setup that somewhat works, although it's probably pretty convoluted and unnecessarily complicated.

This is what I did:

- Create a spiral curve

- Animate a carve-SOP to cut it down from edge to center

- Position the carved spiral at the end of my path curve that's also animated with a carve.

- Fuse the two and create a sweep.

My problem is, however, that I get lots of issues with the UVs and the fusing at the transition between the two.

Maybe one of you experts can have a look at my scene and give me some suggestions as to how to improve my setup?

Thanks a lot in advance

Paul

rolling_road_v004.hip

[gui]

great solution! But I think the fastest way would be using some sort of custom bend tool. My bag of tricks don´t have one that does that, but I will give a try, later today.

[yongbin]

ah... sorry. I have to arrange it. but it's late night here and want sleep.

hip file attached.

maybe tomorrow I fix some more.

rolling_road_v004.test.hipnc

Edited August 7, 2013 by yongbin

[yongbin]

this is more arranged version. see this.

rolling_road_v004.test2.hipnc

[Kaprolactam]

Thank you so much, yongbin, this is perfect. Now I'll just have to figure out what you are doing in there... :-)

[yongbin]

thank you Kaprolactam

but it's not perfect. on rolling side, it's texture slightly moving. at very last step, this effect is more visable. maybe it's not that big problem.. though..

explain some things in here.

carve matching

calculate two curve's length. check it's ratio. (make sure always path's length is bigger than rolling part's length)

if rolling part hasn't carved at all, you should carve path that much(using it's ratio). if rolling part has fully carved and nothing left, don't carve path.

uv matching

if you turn on uv view with last sop, you can see both uv are there and moving.

First I made uv on path then carve. it's carved part uv is gone. so roll part should cover that much. so I scale it.

polyframe

it can calculate tangent/bitangent vectors. those are perpendicular.

tangent is similar with "edge_dir" vector, but it represent slope of curve, not toward next point.

if you have normal "N" before polyframe sop, bitangent is perpendicular to both N and tangent.

if you don't have "N", it will automatically calculate N,

so where will be N on a curve? you can test this with facet sop. just drop facet sop before polyframe sop, and turn on "calculate normal". then you will see it.

align vop - it can transform your vectors(P, N, up) like transform sop but it use A to B method (this case N to Z)

my english is not very good. please, understand it.

cheers

[Kaprolactam]

Thank you for the explanation. Most of it I understood just by looking at your setup, but every bit of information helps. I noticed that I tend to use too many VOP SOPs even though there is a node that does just what I need, for example the PolyFrame that I never used before. Cool stuff.

Cheers and thanks again!

[Parnika]

Nice.