3ds max – Use the Particle-Flow Lock/Bond test to have particles move on a surface in

3ds max 2019

The Lock/Bond Particle Flow test can be used to have particle movement restricted to a surface.


This example shows a simple setup in which the particle teapots have a Speed operator set to Random 3D mode that causes them to move in random directions,
While at the same time the Lock/Bond test forces them to ‘stick’ to the surface:




V-Ray – Underwater rendering tip

3ds max 2019 | V-Ray Next

I decided to do some test renders for an underwater swimming pool scene with 3ds max and V-Ray,
And happily found out that my initial geeky academic approach to the subject was actually outdated and unnecessary.
> look down at the bottom for the correct sample renders.

In this example there is a VRaySun & VRaySky for the daylight render setup and a Caustics calculation to create the light lensing effects on the under water surfaces.

The wrong way:
Having ancient habits in the subject,
I first flipped the water\air surface’s normals so they’ll point down into the water (towards the camera), And set the water material’s IOR to 0.75 ( 1 / 1.333 ) so instead of being an “air to water” material, it will become a “water to air” material.
This produced a non realistic result.
Viewed from underwater, the air surface should have a very dominant mirror reflection at most angles.Untitled-1.jpg


The Correct Way:
It seems that in V-Ray nothing special should be setup in terms of the water material.
You don’t have to create a special water-to-air material like I thought at first.
Its a regular water material, and the water surface is facing upwards like it should,
And when the camera is underwater it renders the water surface correctly as an air surface from withing the water.

The pool water material setup:
Note that Affect Shadows is turned off so the surface will generate caustics and not fake transparent shadows, and that Reflect on back side is turned on to produce more detailed reflections.

This produced the following result in which the reflection/refraction look correct but the water is still too simple:Untitled-2.jpg

Improved wave deformation for the water surface, added detail using a Noise bump in the water material and a sense of depth with Volumetric Fog:Untitled-4.jpg

Finally remembered to activate Reflect on back side at the water material to add more realistic reflection detail, some basic contrast in the V-Ray VFB,
And a shark because I couldn’t help it…. 😀

3ds max – Transform Gizmo disappearing

3ds max 2019

I’ve been operating 3ds max for 20 years and this always gets me by surprise again and again, especially when working with students 😦

In the past, the option to hide/show the Transform Gizmo had a hot key X, and curiously, even though that way it would happen more frequently that the Gizmo would disappear by mistake, when it was X I actually remembered it, and remembered to tell my students to just press X.

The menu command:
VIews > Show Transform Gizmo

I never remember it,
And also, I can’t logically except that it’s a system setting that is kept even when resetting the scene or opening a new file.


3ds max – Unwrap UVW snapping to a defined grid

3ds max 2018

There are cases where we need to have the UV borders and edges placed precisely on a certain grid. an example of this is when preparing a UV layout intended for baked lightmaps in a game engine, that should preferably be aligned to a 64 by 64 or 128 by 128 grid.

To set the Unwrap UVW editor window grid to 64 by 64:

  1. In the Unwrap Options window:
    Set the Checker display to 64/20 which is 3.2.
    Set the Grid Size to 1/64 which is 0.015625 (the numeric field displays the value rounded to 0.016)
  2. Turn on the grid display in View > Show Grid.
  3. In the Unwrap Snap Settings, make sure Grid Snap is checked.
    * Hold and drag the snap button to open the Snap Settings.
  4. Activate Snap.

It works only in Vertex selection mode.