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Extrude perpendicular to nurbs


AlanW

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I can divide a NURBS curve up and I get points. What I want to do is to draw a shape that is perpendicular to a point on the line then extrude out perpendicular to the point on the NURBS curve.

Will keep experimenting.

Thanks

Edited by Alan Woodwell
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I can divide a NURBS curve up and I get points. What I want to do is to draw a shape that is perpendicular to a point on the line then extrude out perpendicular to the point on the NURBS curve.

Will keep experimenting.

Thanks

If you can't get it to work with the EAP, you can also look at using a loft surface instead. It's more work as you will need to provide the shape at evenly spots spread out on the curve, matching the direction of each point along the curve.

I ended up using quaternations, gave me some headache but the endresult is great. :)

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Hippocode,

did you create that with Marionette?

Actual I'm working on something similar, but I'm struggling with the math (vector angle calculation).

I used the SDK.

Rotations on 3 axis are hard to work with, but there are libraries available that can help you with that.

I ended up using the openGL library which is included in the Vectorworks SDK library. You should be able to do something similar with python.

Depending on what you end up doing in 3D rotations, quaternions can help finding out the rotation required between 2 different directions in 3D.

Hi,

What I am after is this by Marionette.

I never could get some of the available NURBS functions to work to find the direction of any point on the curve.

Instead, I chopped it up in a lot of points and used the next - previous point to determine the direction of a point. Then you just need to rotate your object to match it.

Edited by Hippocode
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Patrick.

By the way this was done in VW by creating a Sweep shape and using the Repetitive Unit from the Detailing OIP.

Would be pretty easy to do this in Marionette by using the points on line and using a lofted shape to follow the dots.

Well I think it would be easy , will try.

Edited by Alan Woodwell
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Hi

Why searching so far.

Remember the "Point Array Start-End Node". This is something else that powerfull "Dom-Node" :grin: can do.

It calculates 3D Angle angle between two points. That is the hardest job in that example. After That, your sweep, can be placed by the "PutByRefPoint"-Node.

Try to make this with "native" Nodes, is hard. But I think it is just a question of time, more powerful and complex node will be "native".

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Hi,

So ongoing now we have got this far, the question is how to get Marionette to swap the tread when you are inside the curve and not outside?

Over to you for the day.

PS I know the tread needs some work to relate to the radius so lots to do still but I submit it to the Brains trust for advice.

Edited by Alan Woodwell
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Try using this node:

It checks triangle polygons of the pointlist if they are cw or ccw. It not finish your example but I think with this node, you can finish your stair example. It it gifs you a list of 0 and 1. 0=False (ccw) 1=True(cw) from every input point list (2D/3D)

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Thanks for all the assist, I need to sit and digest this so I fully understand it.

With fitting to the curve I was looking at using the tread node which gave a centre point which generated the inside and outside chord dimensions based on the angle of the segment.

If its a perfect arc or circle this shouldn't be a problem but if inconsistent curve I just need to feed in the radius at that point in the curve and it will generate the correct tapered tread.

Thanks again

Will watch video.

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