Creating Xgen Style Artwork In Houdini

In this tutorial, I'm going to show you how to create artwork like the one below in Houdini. This artwork was popularised by Lee Griggs, using Xgen. Although there are different ways of doing this I'm going to show you the easiest way to achieve this look using the grid surface and extrusion. 

!Note: The quality of this artwork depends on how many times you subdivide the grid.

Version 1: With Diffuse Maps/ Image Textures 

Firstly I'm going to show you how to create this art style with any diffuse map and extrude them based on their colour values.

When you open Houdini create a geometry node by clicking on the Tab key and searching for it. In this tutorial, we're going to name ours Landscape. 

 

Double click on the node or tap the I key to open it. Once you're in, click on the Tab key to open the menu. Search for grid and select it. Set the number of subdivisions. Let's rename our grid by calling it floor.

 

Search for Uv Projection and connect the Uv projection node to the grid node. 

 

To check whether our grid is being properly projected, in the viewport click on Persp > Set View > Uv Viewport.

 

Once inside, your grid will be projected onto it like this. If it isn't like this, try rotating it.

 

Go back to the perspective viewport. Now we are going to connect an Attribute From Map node to the Uv projection node. When connected chose your texture file. 

After that, we are going to create an Attribute Create node which we will rename colour. Then we will set the class to primitive.

 

Here comes the fun stuff. Connect a Poly extrude node to the attribute create node. Change the Divide Into parameter from connected components to individual elements. Extrusion mode to primitive/edge normal. Set your distance of choice.

 

 

Now go back to the Attribute create node. Copy the name and paste it in the Distance scale of the poly extrude node.

 

The last thing we've got to do is go to the Attribute create node. Scroll down until you see value. In the first input type $C+R,G or B. It will either be $CR, or $CB, $CG. This expression makes it possible to extrude the gride using RGB values based on the image texture.

 

You can now bevel it and shade and render it to your liking. 

 

Final Rendered Image.

Version 2: With Height Maps

Creating one with a heightmap uses the grey values to extrude the grid. It is almost the same process but with a slight variation.

Instead of using an attribute create node. We will use an attribute promote node.

Change the original name to Cd and the new class to primitive.

 

After that copy the name of the attribute promote node to the distance scale in the poly extrude node and voila!

There are many ways of doing this artwork. You can do it by instancing, or even by scattering. All come with their pros and cons if you have a better way of doing it kindly share it in the comments. 

Thanks.