Scene Nodes Introduction

Introduction

Nodes are nothing new for Cinema 4D users. The XPresso System and of course the Material System have been part of Cinema 4D for several versions now. The Nodes System makes individual functions available as Nodes, which are displayed as a graphical element that can be connected with other Nodes to exchange specific information. Connecting multiple Nodes can – just like a programming language – be used to execute calculations or specific functions. For technically-oriented users in particular, this bears the advantage that custom assets can be created for recurring tasks, i.e., custom functions and tools can be created. Nodes also make it possible to access functions that are only partially or not at all accessible via normal commands or objects in Cinema 4D – and this without using programming commands or having to know programming code!

Now this concept can be used to create geometry in Cinema 4D. You can, for example, create custom Deformers or entirely new distribution functions for clones. This is what can be done with the new Scene Node Editor, which can be accessed via the main Window menu in Cinema 4D. The look, functionality and use are nearly identical to the Material Node Editor, which can be used to create Node-based materials.

The Scene Node Editor can also be displayed in the left column of the Node groups and assets from which they can be dragged into the Node Editor as needed. The Scene output on the right side of the Node Editor, however, is new. This is basically your connection to the current Cinema 4D scene. If objects are created within the setup, these can be connected directly to the scene via the Scene port and they will appear as normal geometry in the scene. You will have to get used to the fact that these objects don’t also appear in the Object Manager. Everything that has to do with these Node objects is done exclusively in the Scene Node Editor. Here you can create, place, group objects and apply materials to them.

Generate or create geometry

The Scene Node tools also offer the common primitives that can be generated. An example of this can be seen here:

A Primitive Op Node is used to generate a cube. This Node’s output can be connected directly with the Scene but then you would not be able to position or rotate the cube freely. We will therefore add a Compose Matrix Node, define the desired position and rotation and link this matrix with the cube via a Matrix Op Node. The Matrix Op Node’s output contains the position information for the cube and can be sent to the scene. The cube will then appear at the defined position with the respective rotation in the Viewport.

Since more and more roads lead to Rome we you can also get more into detail because the cube shape can also be called up as a Geometry Node. Contrary to the Geometry Op Node, this Node does not offer the possibility of switching to other primitives and only offers a single Geometry output, which basically only contains the information pertaining to points, edges and polygons. Other typical object information such as a freely definable display color or the option of being hidden in the Viewport are not available here. This information can, however, be added via a Geometry Op Node in order to make an object out of geometry:

The greatest amount of control over geometry is offered when you create it yourself using points and edges. You can, for example, use your own point order or execute mathematical calculations to create abstract shapes.

For this, Arrays must be filled with values, which can be done using a Build or Index Array from String Node. You can imagine Arrays as a list with different consecutively numbered values. This should already be familiar to you from the Structure Manager where a polygon object’s points and polygons can be displayed as such in a list.

The Polygons Topology Set Node can be used to set the points’ numbers that belong to a given polygon. Since this series of numbers does not contain information regarding, for example, if polygons should be created as triangles or quads, you will have to add an Array that contains the number of points for each polygon that has continuous edges. This information will be named Border in the Node. Finally, the information regarding the number of borders that the polygon should have is missing. Normally, this will only be one border but N-Gons can, of course, also be generated that have a hole. In this case, a border for the outer shape of the N-Gon and a border for the opening will be defined. This information will be named Groups in the Node. Together, the information about the point indices, borders and groups is referred to as Topology and can be combined to create geometry via the Geometry Property Set Node. To do so, the position of all points must be set. For this, an Array will again be required that is defined via a Build Node as seen in the image below.

Splines can also be drawn in a similar fashion.

Modeling Funcitons

Modeling functions

Common modeling functions such as Extrude, Extrude Inner and Bevel are also available and can be restricted to specific elements on a geometry via a selection.

Here, Arrays can also help by passing the indices of selected points or polygons to the modelling commands. A special type of Array is needed to select edges because edges are only defined by their end points.

However, the Index Array from Text Node can be used in both cases to define the indices of the points or polygons. An Active Selection Node can be used to output a saved selection (via Set Selection Node) or to directly select input indices on the geometry.

Subsequently added modelling Nodes will then automatically be restricted to this active selection. Alternatively, indices can be passed directly to the modelling Nodes. In the following image you can see all commonly used variations for handling selections.

The green marked Nodes uses a list of point indices to create an active edge selection, which will then be extruded.

The yellow marked Node contains the index of a polygon that is subsequently deleted using a Remove Node. The red Nodes also use a list of indices that is saved under a unique name via a Set Selection Node. The following Get Selection Node reads the selection with that name and passes this to a Polygon Bevel Node to extrude the caps surface in a pyramidal shape.

Creating and managing multiple objects

No matter how you create objects, only one Object output can be connected with the scene. If you want to create multiple individual objects you can, for example, us a Children Op Node to combine multiple objects and send them into the scene:

This way, object hierarchies can also be created.

If you want to duplicate objects you can, for example, use a Distribution Op Node, which can be used similarly to the MoGraph Cloner object. A linked object will be cloned at the defined positions and can then be sent directly into the scene. The Color Op Node can be used to color these clones individually. In the example image below, a Hash Node was used to randomly generate colors.

If you need even more control you can arrange the geometry for the calculated positions yourself using the Distribution Op Node to output matrices that can, for example, be connected to a Matrix Op Node with objects :

In this example you also see how objects from a distribution can be deleted. Here, a mathematical Modulo with a value of 2 for the clones’ index numbers is used to only deliver results between 0 and 1. These values can be interpreted as Boole values via a Filter Op Node, which will result in every other object automatically being removed. A typical beehive or brick pattern will result.

Of course the position and shape of the copies that are created can be modified. Various Effectors are available with which this can be done. The Effector Op Node offers a wide range of common deformations such as Bulge, Taper, Twist and Bend. You can also create custom algorithms via an Effector Group Node. Separate fields, which can be selected via a Field Op Node, can be used to spatially restrict the effect of the deformation n: