Making reflections in Poser 6 - 1

This tutorial was produced with Poser 6 but should also be applicable to Poser 5. It will not be useful in Poser 4, which does not have raytracing. This article does not cover the use of reflection maps, only true, ray traced reflections.

Getting started

The basic steps involved in making an object reflective are known quite widely. You add a reflect node to the object which is to be reflective, turn on raytracing in the render options, and make sure there’s some other object(s) to be reflected in the reflector. Then render.

Except that sometimes the results aren’t what you expected. There are a lot of options which can alter the appearance of a reflection, and the purpose of this tutorial is to work through these. I wrote this after getting quite frustrated trying to make reflections as I wanted them, so I hope it might stop you feeling the same way.

First, let’s produce a scene to use in the tests. This scene just about as simple as it could be. Here’s how to set it up:

start a new Poser scene
add a cylinder from the Primitives folder in the Props category, and yScale it to 300%
switch to the main camera and dolly out along the z-axis so you can see both the cylinder and where its reflection will be on the ground plane
make the ground plane visible (in Poser 6, you also need to turn OFF ‘Shadow_Catch_Only’ on the ground plane in the material room)
use just one light, an infinite light shining towards the lower back right hand corner as you look at the screen. Make sure the light colour is pure white and intensity is at 100%, with shadows set to 0.5
go into the Material room and first set the cylinder colour to pure yellow (RGB 255, 255, 0)
then set the ground plane colour to pure red (RGB 255, 0, 0); sorry about the lurid colours but there’s a point to this
add a reflect node (new node->lighting->ray trace->reflect) to the Reflection_Color channel of the ground plane – leave all the Reflect node values at their defaults
go back to the Pose room, go to render settings and turn on ray tracing; set ray trace bounces to 2 and leave everything else as it is
the scene should look like Figure 1 (really exciting!) when complete

If you don’t want to set this up, you can download the scene file here (8K zip file).

In this tutorial, I refer to the object doing the reflecting – the ground plane in this case – as the ‘reflector’, the object being reflected - the cylinder - as the ‘reflected object’ (surely not!) and the image of the reflected object in the reflector as the ‘reflection’.

Figure 1.

Section 1: interaction between the Diffuse_Color channels of the reflector and the reflected object

Okay. Try a test render. It should look like Figure 2. Note the very bright, clear reflection; also note that the reflection colour is orange. This is what I think we would expect. The floor is red; the cylinder is yellow; the reflection colour should therefore be a combination of the two, orange.

Figure 2.

Now change the floor colour to cyan (RGB 0, 255, 255) and re-render; the reflection colour is now light green (Figure 3).

Figure 3.

So, here is reflection rule number 1:

R1. The colour of the reflection is a combination of the reflector surface colour and the reflected object surface colour (provided that the Reflect node Background colour is black and the Reflection_Color parameter that the node is plugged into is white – see below).

Set the floor back to red and now change the cylinder colour to black, then re-render (Figure 4).

What happens? There is no reflection of the object itself but there is a reflected specular highlight. This is logical but not quite as we would expect in the real world. Logically, a black object is one which reflects no light, and in that case there can be no reflection. If you turn off the specular highlight on the cylinder, you will see no reflection at all although the black cylinder is clearly visible in the scene.

Figure 4.

This gives rule number 2:

R2. An object which is pure black in colour may be visible in the scene but will not be visible in a reflective surface, although its specular highlight may be.

Finally in this section, change the cylinder back to yellow and the floor to black, then re-render (Figure 5).

Figure 5.

The reflection colour is now yellow (actually a rather dirty yellow, but we’ll fix that later) which gives rule number 3:

R3. To make a perfectly reflecting surface, the Diffuse_Color of the reflector must be set to pure black (RGB 0, 0, 0).

Page last updated: February 2nd 2006