How to do Splashes

Splashes simulate water drops that splash (upwards) after hitting a (nearly) horizontal surface. This is easily visible on many buildings. Effects from splashes start very early, even when a building is just a few weeks old. Like rain drops that hit the ground (earth/sand) and add this to a wall.

Step by Step

1. A copy of the tutorial model for mental ray is available here. For the V-Ray version click here. For RichDirt2 mr click here. For RichDirt2 vr click here. Load the model, ignore the warning about a missing wind.jpg (some versions of 3ds Max) and Render the scene:


Expert user can skip steps 2 to 6 (the first 6 steps are shared among tutorials).

2. Open the Compact Material Editor. Create a new Multi/Sub Object material. Name this ´myMultiSub´.

3. Create a new mental ray Arch and Design material or V-Ray material. Name this ´myWallMtl´.

4. Open ´myMultiSub´ material again. Add ´myWallMtl´ to slots 2,3,4,5 of myMultiSub. Make sure to use -instances- (not copy, we want the same wall material used 4 times). See the ´Natural Variations´ tutorial for a snapshot of the UI. Also copy material ´mirror´to slot 6 - this is used for the windows.

5. Now go back to ´myWallMtl´. Click the diffuse color map button, to add a RichDirt texture. RichDirt is found in the map section of the material and map browser. Starting with version 1.1 you find it in the standard maps (not in the mental ray or the V-Ray specific maps). Name the texture ´WallDirt´.

6. Make the Dirt color -blue- and do a short test rendering. Select the wall geometry in the viewport. In the material editor press the ´Assign Material to Selection´ button. If everything worked fine you should see some blue around the windows. In version 1.06, and higher this will be stronger than in the image below :

7. Now add splashes
Go back to the ´WallDirt´ texture. Select the ´Splashes (Variations)´ preset. Also change the ´Clean´ color to rgb 0.973, 0.871, 0.612. Now render again :


Wow ! This created natural structures in just a few seconds - at the right place !
Using the right perspective.
To get more insight a few words on the ´Splashes´ preset: It uses a ´Bias Z´of 50 (positive) to get the AO rays directed downwards. There is -no- IO active, as splashes in nature only happen on objects that stick out of a facade. Ignore bump is switched on as well. Typical splash (drops) jump from an obstacle back to the facade, and thus bumps on a facade do not matter. Last but not least - Splashes use Streaks (AO), with a quite large noise - combined with a very wide spread of 55 degrees. This huge spread keeps the sharp details close to the edge, and helps to fade out into a smooth structure further away.

8. More ? Try the following 3 scenarios:

a) use a larger falloff, like 5.0. This creates more grain.


b) use a larger streak Builtin size - 27.0. Removes the smaller details.


c) use a ´lower edge´ value of 5.0 (in the main rollup). This makes the splashes even longer.


9. Splash color. The previous steps used blue, which isnt natural. What is the ´real´ color ? It depends on what your goal is. Sometimes splashes transport earth/sand. Then the color would be brown. Sometimes splashes make a facade wet - then it can be green (moot) or black (funghi). Sometimes splashes clean a facade (wash dirt away).
The image below simply uses a darker and more saturated color. Changes to the tiles are a bonus.

Copyrights
mental images and mental ray, are registered trademarks, and are trademarks of mental images GmbH, in the U.S.A. and/or other countries. V-Ray and the V-Ray logo are registered trademarks of Chaos Software Ltd. in Bulgaria and/or other countries. Autodesk and 3ds Max are registered trademarks or trademarks of Autodesk, Inc., and/or its subsidiaries and/or affiliates in the USA and/or other countries. finalRender is a registered trademark of cebas Computer in Germany. All other brand names, product names, or trademarks belong to their respective holders.