How to use Caustics in SU Podium


This video begins with a definition of caustics, and then explains how to use the feature in SU Podium.

Caustics is an on/off switch in the environment tab of the options dialog, however in order to use the feature effectively it is necessary to edit some values in the SU Podium preset files. This is very easy, but in order to edit presets you need to know where they are saved on your computer:

Where to find the preset files:

On both Windows and Mac you will need to show hidden files in order to find the preset files. On Windows, switch to the view tab in Windows Explorer and check the "hidden items" checkbox. On Mac, press Cmd+Shift+Period inside a Finder window to reveal hidden files. Open preset files in any plain text editor to make changes (Notepad, TextEdit, etc).

Windows preset location:
C:\Users\Username\AppData\Roaming\SketchUp\SketchUp 20xx\SketchUp\Plugins\SU_Podium_V26\presets

Mac preset location:
MacintoshHD/Users/Username/Library/Application Support/SketchUp 20xx/SketchUp/Plugins/SU_Podium_V26/presets/

Edit preset files in any text editor (Notepad, TextEdit, etc.) - Before you edit preset files, it is recommended that you duplicate the file and save it as a backup of the original version. This way you can revert to the original if you make changes you don't like.

Which preset parameters control caustics?

There are six variables in the interior and exterior high presets that control the quality of the caustics result in your render.

var __cphotons, -100000;
var __cN, 600;
var __cmult,1;
var __csteps,10;
var __clow, 0.1;
var __chigh, 0.9;

These parameters are ONLY found in the "High" quality presets. If you would like to use caustics with the "Default" presets, copy the parameters exactly as shown and paste them into the interior/exterior default preset.

What do these variables control?

The first three values have the most noticeable affect on the quality of the caustics in your SU Podium render.

var __cphotons, -100000; — Controls the number of caustics photons. This is the most important value pertaining to the quality and accuracy of SU Podium caustics.

Increase this value to improve the caustics quality, but always leave the negative sign before the number. -100000 is the default value; -500000 would mean you have increased the number of photons 5x. Adding more cphotons does increase render time.

var __cN, 600; — Increasing this value blurs the caustics photons, while decreasing it makes them sharper. Increase the value from 600 if you want softer/smoother looking caustics. Does not affect render time.

var __cmult,1; — An intensity multiplier. Increasing this value will increase the brightness of the caustics. Does not affect render time.

We do not have comprehensive information on csteps, clow, and chigh. They do not seem to have much affect on the caustics result. Will update if more information becomes available.

Related pages and articles:

SU Podium written tutorials

Tutorials Page - Written Podium tutorials and other documentation.

SU Podium video tutorials

Additional videos - Videos that aren't part of the getting started series.

Upgrade to SU Podium V2.6

Upgrading to V2.6 - What's new in V2.6? Download the update here.

Exterior residential render

Intro to Rendering - A written introduction to Podium rendering, with step by step images.

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Support hub - Click here if you are having trouble getting started