Author Topic: Double Helix  (Read 7865 times)

Offline old_blaggard

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Re: Double Helix
« Reply #15 on: July 21, 2007, 06:40:04 PM »
Ah, that makes sense.  Thanks :).
http://www.terragen.org - A great Terragen resource with models, contests, galleries, and forums.

Offline bigben

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Re: Double Helix
« Reply #16 on: July 22, 2007, 12:52:23 AM »
Very cool nikita.

Maybe math teachers should introduce TG2 into classes to make math more interesting/ practical  :)

Offline Volker Harun

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Re: Double Helix
« Reply #17 on: July 22, 2007, 07:18:22 AM »
Worth while patience! Thanks for sharing the technique!

Offline Volker Harun

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Re: Double Helix
« Reply #18 on: July 22, 2007, 08:06:59 AM »
What I do not understand, why do make x and z, combine them to one scalar and make a square root - you can just delete all those nodes.

Offline nikita

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Re: Double Helix
« Reply #19 on: July 22, 2007, 11:51:52 AM »
sqrt(x+z) is not equal to x+z
(unlike sqrt(x*z) = x*y)

Of course you could delete those, but then you wont get a cone but a pyramid. :)

Offline Tinga

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Re: Double Helix
« Reply #20 on: July 22, 2007, 12:09:24 PM »
Thanks for your tutorial, Nikita :)

Offline Volker Harun

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Re: Double Helix
« Reply #21 on: July 22, 2007, 01:12:53 PM »
Hi Nikita,
well, x and z are not added in a numerous way but are combined to a scalar, where x and z are handled seperatly, aren't they.
For example x=4 and z=4 then the addition is (4|0|0)+(0|0|4)=(4|0|4) - if I should be right then the nodes can be deleted.
And a testrender shows a cone, not a pyramid.

Offline nikita

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Re: Double Helix
« Reply #22 on: July 22, 2007, 01:39:24 PM »
If I delete them, the cone turns into a wall or a pyramid if i add the necessary abs()'. There is no way you could get a cone without using at least the x2,z2 nodes.

This is the way how I understand it works:
X to scalar: (x,y,z) -> x (the function assigns to a vector its x-component [and doesn't remember that this has once been an x-value])
Y to scalar: (x,y,z) -> y
...

A scalar, that handled xyz seperately would be a vector. Why would we need the concept of a scalar if it was just a special form of vector?

Offline Matt

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Re: Double Helix
« Reply #23 on: July 22, 2007, 01:58:14 PM »
If I delete them, the cone turns into a wall or a pyramid if i add the necessary abs()'. There is no way you could get a cone without using at least the x2,z2 nodes.

This is the way how I understand it works:
X to scalar: (x,y,z) -> x (the function assigns to a vector its x-component [and doesn't remember that this has once been an x-value])
Y to scalar: (x,y,z) -> y
...

A scalar, that handled xyz seperately would be a vector. Why would we need the concept of a scalar if it was just a special form of vector?

That is correct Nikita. Scalars only remember one component, but if you later feed a scalar into a node that expects a vector (or colour) it will copy the scalar into each of the 3 components.

Matt
« Last Edit: July 22, 2007, 02:02:55 PM by Matt »
Just because milk is white doesn't mean that clouds are made of milk.

Offline Volker Harun

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Re: Double Helix
« Reply #24 on: July 22, 2007, 02:03:58 PM »
You are right, but you are adding two different ordinates not two Xs.

See the attached image that 'if' you delete it will not be a pyramid.

Offline Matt

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Re: Double Helix
« Reply #25 on: July 22, 2007, 02:06:56 PM »
Hi Volker,

This works in TG2 because TG2 conveniently converts vectors into scalars by taking the magnitude of the vector if you don't explicitly specify how that conversion should take place :-)

There is also a function in the Convert menu called "Length to scalar" which does the same thing.

Matt
« Last Edit: July 22, 2007, 02:10:55 PM by Matt »
Just because milk is white doesn't mean that clouds are made of milk.

Offline nikita

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Re: Double Helix
« Reply #26 on: July 22, 2007, 02:14:04 PM »
That explains everything  :)

Offline Volker Harun

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Re: Double Helix
« Reply #27 on: July 22, 2007, 02:22:16 PM »
I had my final exams in maths - it was about vectors in 4-dimensions - I remember now very good, why I almost failed :D
But I 'd rather like to stop spamming this thread. Again I was just lucky with what I was doing ,-)

 

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