# How to model this sand dune as one surface

Hi,

How do I model a continous surface with a few of these sand dunes (see img below) appering on the surface. At the same time I want the part which I have hilighted in red to be cut through so you would be able to see through it.

Appreciate any suggestions!

For the dune to be a continuous single surface Iâ€™d say you use multiple curves that define the shape of the dune. Something like intersections of the dune and the sand around it with vertical planes parallel to the direction of the wind. Then use Loft with â€ślooseâ€ť option

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sweep 2 rails ?

for example

i did something same last month :

model :

render:

I am not sure I understand do you mind doing a quick sketch of what you mean?

ok so sweep 2 rails but how is it possible to attach it to a plane so naturally like the model.

This:
Untitled.3dm (72.3 KB)

in order to get your shape you need to add more points and form the sand-wave

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thank you that helped!
aha so basically you draw multiple sections of the sand dune and the flat sand at different levels and and then loft it.
but did you define the curve from plan view first

I made a simple case. What I did was think how many points I need to define the most curvy part of this wave. So I created a single nurbs curve with that many points along 0x axis. Then copy it over in Y direction in n number of times and I started moving points by pairs (so that the wave is symmetric).

You can do it differently, You can simply create a planar surface, rebuild it with n-number of U rows and m-number of V-columns. Then you just adjust play around with the points

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say I have multiple surfaces with diff waves is there a way to stitch then together for cnc later?
I mean so its one continuous surface with no division.

The only way I see this happening is if you convert your multiple-surfaces into meshes then convert it in a single surface. But I canâ€™t help you with this I know nothing about mesh

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Thatâ€™s not how models need to be prepped for CNC, they donâ€™t need to be one surface. They just need to be â€śjoinedâ€ť together, thatâ€™s the whole point of NURBS.

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They donâ€™t need to be â€śoneâ€ť surface for CNC, the different surfaces just need to be â€śJoinâ€ť-ed into one polysurface.

If this was answered to me. I didnâ€™t say this is how you do it for CNC. just how would you do it to be a single surface Currently I have no knowledge about CNC preparations.

Not even in most cases. If surfaces overlap, most CAM programs will only cut the topmost surfaces, so you can ignore anything that is â€śunderneathâ€ť and not have to try to trim/join anything (if youâ€™re lazy)â€¦

Well, yeah, just trying to not encourage utter sloppiness!