The Curve class is the base class for several core threejs Classes to create a Curve in space. There is then a Cuve class prototype method called the get point method that can then be used to get any point along a curve in the form of a Vector3 object, or Vector2 object for 2d curves, by passing a zero to one value as an argument. For the most part thus far I have been using curves as a way to define paths than can then be used to set the position of object3d objects over time such as mesh objects, and cameras. I have also been using curves to get vector3 objects that can then be passed to the look at method to set the rotation for objects also. However I have not yet got into using curves as a way to define the position attributes of custom buffer geometry objects which is what this post will focus on.

There are both easy, and not so easy ways of making a gometry from a curve. When it comes to 2D curves there is creating a shape object, and a Shape or Extrude geometry can be made from that. There are also ways of making a 3d shape from a 2d curve by using the Lathe Geometry class. However there is also of course 3D curves as well and using them to help in the process of creating a cusotm geomerty from the ground up.

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The index property of a buffer geometry instance in threejs is a way to define an array of index values in a position attribute that will be used to draw triangles. Simply put it is a way to reuse points stored in the position attribute so that the over all length of the array in the position attribute is lower than it would otherwise have to be. The main reason why I might want to have a geometry indexed is to save memory when it comes to geometries with a lot of points in them. Also it would help to reduce the amount of overhead it would take to update geometry also a little as it is less points that have to be looped over in order to do so.

However there are also some draw backs with this as well that have to do with the state of the normal attribute the corresponds with the position attribute for example. Also because I am reusing points any kind of effect that has to do with exploding a geometry into a hole bunch of single triangles is not possible as the points are being reused. It is not so hard to convert an index geometry to a non indexed one though, doing so involves just calling the to non indexed method of the buffer geometry class. Things might be a little involved when it comes to the other way around though as it will involve creating a buffer attribute instance and using the set index method.

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When looking into the built in Geometry Classes in threejs for the first time there are a few that can be used to make a Pyramid Type Geometry. Both the Cone Geometry, and the Cylinder Geometry classes can be used to do so if one gives a certain set of arguments when calling them. There is however also a built in Tetrahedron Geometry Class that can also be used to do this by just simply calling it and giving a radius that will also result in a Pyramid shape as well.

However one might run into some problems with this sort of thing when it comes to rotation of the result, and there are also a few additional reasons why one might want to make some kind of custom geometry for this sort of thing as well. So in this post I will be writing about this built in Tetrahedron Geometry Class, but also an array of alternative ways to create this kind of geometry including some custom ways to do so while I am at it.

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There are a lot of ideas that come to mind when it comes to making an electronjs project example, one of which would be to make a file manager. This is one of many project ideas where getting the core set of features working might not take to long, but in the long run can turn into a major project that can take months, or even years to refine if doing so is justified. The starting point I had in mind was to just have a way to navigate around a file system, and be able to start a terminal window at the current working folder. Just that alone is simple enough for sure, but then there is working on the additional basic features that one would expect of any file manager, and how to go about doing just that. There is working out javaScript solutions for everything, but then there is also the idea of using the child process module to make use of binaries that there are to work with in the underlaying OS and being done with it.

This will then be a post on the current state of an electionjs project where the aim is to start making something that is at least starting to look like a file manager program. Like many of these examples thus far I will want to keep the bar low for now unless I do start to use this all the time, or people take interest or so forth. The main goal then is to just be able to navigate around folders, and then start a terminal window or alternate file manager at the current path. On top of that there is also getting this to work on the operating system that I use most of the time which for now are windows 10 and Raspberry Pi OS.

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The THREE.Curve base class can be used as a way to create custom curve constructor functions, but one might need to even bother with that as there are a number of great built in curve constructor functions as well. In any case Curve objects, regardless if they are custom , or built in, are a great way to go about defining paths in 3d space. I am sure that they may also be useful for many other things in threejs such as creating the position attributes of geometry, but for now I am mainly focused on using curves to define paths that can be used to define the movement of objects over time.

In any case I will want to make a threejs project example that is a javaScript module that contains tools to help me do various typical things that I want to do with curves in threejs. This module will have a number of tools that will help me to create Cuves, as well as arrays of vector3 objects using curves. I also have a number of methods that I can use to create what are often called alpha values as well using curves, as well as a number of other methods that can be used to debug what is going on with these sort of things. So in this post I will be writing about the source code of my current standing curves module as well as a number of demos that make us of this module.

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