Tweaking

Tweaking.

Once the particle-systems are created you might want to quickly adjust them.

In the tweaking panel, you'll be able to change a few controls in the Scattering and Clustering sub-panel, where all properties are densely packed together for a fast and effective manipulation.

In "Tweaking" > "Scattering" > "Particles", the first column of properties are dedicated the the particles density.

  • Emission count is your main particle emission amount, it is the total amount of particle instances created by the layer.

  • Emission density is an operator that will change your particle count property with a particles number per square meters / kilometers estimation*

  • Emission Coefficient is an operator that will multiply or divide the emission count by a desired number.

  • per face/ per vert operators will distribute the particle per faces / vertices and change the particle count amount accordingly.

*in 4.0 a new option was introduced to take the concerned masks area into consideration when calculating the final particle count.

The Second column is dedicated to the scale of the instances.

  • Particle scale will change your particle scale

  • Random scale will reduce the scale of the particles randomly.

note that you can also change the scale of the instance directly in the viewport.


The Third column is dedicated to the rotation of the instances.

  • Random Rotation Z, XY will randomize the rotation on a Z/XY axis.

  • ZGlobal will orient particles from global space Z axis, ZLocal from a local object space Z axis, Normal from faces normal direction, Hair from a hair seed orientation method.

note that you can also change the rotation of the instance directly by editing the mesh instance.

Clustering.

You can Influence the particle instances distribution with a texture data.

In the Clustering sub-panel you can choose up to two textures, either procedural cloud noise or bitmap, to have an influence over your particle scale or density.

You can tweak your influence quantity, texture color brightness or contrast, texture projection, scale and offset. There's multiple randomization options available to quickly iterate through designs.

You can add your own distribution textures in the Scatter Asset Library / __textures__ folder (This folder can be opened with the folder icon).

Note that the vertex-group mask workflow also propose a texture-density solution, you might want to choose this solution if you'd like to export your final particle scattering map or have a texture influencing multiple particles at once (with reverse influence options for example).

Add Childs around each particles.

When working with extreme amounts of particles, children may help you.

When the children option is activated, Blender will add more child instances around your initial instances locations.

You may want to use the children option when you are working with an extreme amount of particle, for example when scattering immense forests or fields composed of tiny grass blades, composed of millions of instances.

Please don't use this option for simple scattering as it will add an unnecessary layer of complexity on your workflow.

Batch.

Change multiple particle systems peoperties at once.

When you have multiple particle-systems selected at once, all sliders in the Scattering and Clustering panels will batch apply values to selection.

With this batch tweaking method, you'll be able to batch change or batch randomize your particles parameters extremely quickly.

Replacing/ adding more Instances.

Your particle number is what will mostly cripple your viewport refreshrate.

In the Instances panel you'll be able to quickly add or remove particles instances.

The instance panel is also handy for multiple operations:

  • You can select your particles quickly (and alt-click to center viewport on the instance).

  • You can quickly change instances object relations tracking axis values.

  • You can quickly set the particle instances object display as bounding box.

  • You can quickly have an access to your LOD status.

Selection Tips.

A few handy shortcuts.

In the selection area:

  • Shift -Click to select multiple particle at the same time.

  • Alt - Click to select and isolate the particle layer (can also be combined with shift).