Scatter tutorial with Particle Flow
Posted on 2012/10/08
After a while unpublished, for professional reasons, I have decided to post a tutorial on how to scatter different objects.
This tutorial serves to scatter several elements in a scene, such as grass, trees, rocks, leaves … It has 2 levels, level 1 is the basic particle flow (flat surfaces) and level 2 advanced particle flow (curved surfaces).
We will use the native 3d studio max particle system.
PARTICLE FLOW WITH DISPERSION
To begin with, we have the surface to scatter, (a plane) and the object that we will be scattering, in this case a teapot with material assigned.
You can also uses proxies as a particles if you want to scatter a heavy polycount object, but in this case our teapot is very light so it isn’t necessary, also particle flow has different types of visualization methods to don’t overwhelm the viewport with geometry.
Let’s open the particle flow, click number 6 or Graph Editors/Particleview.
Once opened, click the right mouse button in the gray area and choose New/ParticleSystem/ StandardFlow (like this).
We will change Emit Stop Value from 30 to 0, now all particles are generated in the initial frame. With the amount option we can control the quantity of particles scattered.
The next step is assign the object that will contain particles. To do this, change the following element Object Position by Position Icon. To change this, right click above Object Position and select insert/operator/object position. Once changed, go to the right panel and in the Emitter object section, select Add and click the surface to scatter (in this case the plane).
In section Uniqueness, Seed value changes the distribution of the dispersion, to change, click New.
The next step is delete the item Speed001, select right-click Delete.
The next element, Rotation, on the right panel in orientation matrix section, select Random Horizontal. This causes the scattered objects to rotate randomly 360°.
To give a little random inclination to each of the elements, we can set a value of 5 or 10 in the divergence.
Select element shape 001 and change it to shape instance, right button insert/operator/shape instance. In the Particle Geometry Object section, select none and click the object of the scene we want to scatter.
The value of the Scale, scale particles respect to the original. Below, Variation, with which we can input how the scale varies respect to the original.
Finally, Display controls how Particle Flow shows the scattered elements. In the type can choose the display type.
Particle Flow by default, shows 50 percent of elements dispersed in the view port. To view all elements, select PF Source and the right menu in the section of Quantity Multiplier change the value of Viewport % from 50 to 100.
At level 2 we will add a number of variables for Particle Flow to act in certain areas, is perpendicular to the normals, density control, etc…
Location, with this section of the element, Position Object, we can modify the following options.
Make the Particle Flow acting on a given area.
If we choose selected faces in the location drop-down menu, and we select the faces of the element that will contain the scatter, with the poligon subobject of the editablepoly, the Particle Flow only makes us the scatter in the selected polygons.
We can define the area of action in the Particle Flow by polygons, edge or vertex.
The Surface Offset parameter allow us to control the minimum and maximum displacement in the z axis of the objects scattered.
The Density by Material allows to control the density of the scatter with a black and white texture if we assign a grayscale texture on the material of the plane.
The Spacing controls the distance between particles, to make it all more evenly distributed.. The separation depends basically on three values:
Distance, Attempts max and the amount.
Distance: more value, more evenly distributed will be
Attempts max: more value, more evenly distributed will stay.
To get a more or less uniform dispersion, play with these three values.
View video for see the previous examples.
Align to normals
If we have a curved surface, as explained so far, is not possible to align the objects with normals. To align objects to normals we will:
Insert a Speed by surface below the Position Object, in Surface Geometry of Speed by Surface click add and select the curved surface of the scene, in the section of Direction make sure surface normals is selected.
In the Rotation element, change Random Horizontal to Speed Space and change the angle of the Y axis to 90.
Finally, insert the icon Speed under the item Rotation and modify the Speed Value from 300 to 0. This is so that the particles have no movement if accidentally we move the time line.
We can add the item Scale for more control, it will let us add random scale values to the scattered particles.
I hope you liked it. Thanks.
Tutorial made by Toni Fresnedo