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Scatter on geometry only on Y-Axis

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Hello,

I am building a simple cave system.

The cave itself is a spline -> copy a circle to points -> skin it ->  and finaly bool the tunnel into a cube.

Now I would like to scatter points on the cave ceilling, to have anchor poitns for cables and lamps.
I attached an image to show what I mean.

I though, I could maybe use the exsiting spline and the upvector to somehow alow the points to scatter only on the ceilling - but I have totaly no idea how to do that.
Also about the cables - is there a tutorial, that shows something similar?
Like generating a spline between the points and give it gravity to let it hang down between the anchor points.

And another question is, if there is some way to erode the tunnel.
I guess, with HF Project I cannot modify the tunnels inside the box - is there another way to kinda fake erode?

Thx alot!

edit: I wanna create something like that: https://blog.csiro.au/kids-raid-caves-in-virtual-classroom/
So the points on the cave ceilling also could be used to create stalactites or on the floor a way system etc.

Edited by sant0s81

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Use bbox to isolate top of the cave and then scatter there by attribute.

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Hello

You can create point group of circle before copy to points then after skin promote point group to primitive. After boolean this group has to project to the box geometry. Use this group for scatter. See the hip, I hope this helps you.

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Hey,

thx for replyling!

One thing I forgot to mention - I wanna keep it procedural since I have to modify the curve / tunnel.
So it would be great, to not always group the geometry like in ur example @vicvvsh.

i thougth, I could for example just use the exsisting spline and transform it in the y-axis only until I am near the closest points of the tunnel.

Than use that spline (points of the spline), to generate a weight map on the tunnel geometry, that I can expand by distance to points, add a fractal to get more variation etc.

In Softimage I would just use the curve, move it up in the upvector, shrink wrap it to the geometry and than generate a weight map by distance to the spline points.

Thats what I try more or less in Houdini atm.

Thx again

Cheers

Edited by sant0s81

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So many ways do do stuff like this. Grouping based on normal direction works good, but maybe projecting the base curve upwards and transfer from there is bett

cave.hipnc

Edited by mawi

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Hi Salomon,

in order to scatter points on the cave´s ceiling only, compare the surface normals with the direction towards the curve. Modify the resulting angle to control the scatter density.

Edited by konstantin magnus

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9 hours ago, sant0s81 said:

One thing I forgot to mention - I wanna keep it procedural since I have to modify the curve / tunnel.

So it would be great, to not always group the geometry like in ur example @vicvvsh.

I wouldn't say that it not procedural because all groups created procedurally ... but it's up to you

Another example without a single group

P.S. there is one group actually )

Edited by vicvvsh

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Good morning,

thx u guys alot for these examples - lots of great input and super usefull.

I am gonna study them now.

In your example @vicvvsh I just added a fuse node to evenly snap and delete the points and already have the lamp setup - thx alot.

Cheers

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