Project Primitive Deformer

The bigger ‘cube of dotted lines’ is based on the volume of the object you have, in this case, a sphere. The inner smaller cube of dotted lines is the volume of the primitive object we are using to affect the mesh. So, because the primitive is clearly smaller than our object and sitting inside of it, we can’t see any changes.

NOTE: if your primitive doesn’t look anything like the image below, make sure you click ‘Full reset’ from the deformers popup window to set it back to the defaults.

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Clearly, the most obvious difference between this and any other deformer is that the Gizmo is still visible. However, the gizmo is only there to affect the primitive that we are using to deform our object. Let’s push the primitive up a bit (with the gizmo):

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Done, this is the basic function of this deformer. You can clearly see that the primitive is a smaller sphere, and when we push it upwards, that top area of our object is being altered to conform to the primitive object… we are ‘projecting’ a primitive object.

At this point, we can move the primitive even higher and you’ll see that there is a ‘threshold’. Once you pass a certain point the primitive is still being projected but with an inverted effect.

An easier way to explain that threshold is with percentages:
BB = Bounding Box of the primitive shape
> 50% BB outside the main objects bounding box = Project inwards
< 50% BB outside the main objects bounding box = Project outwards
= 50% BB outside/inside the main objects bounding box = Weird inverted normals (avoid that).

Now in terms of the controls (cones), I’ll do my best to explain them individually, but I think the best way to learn how they work is by playing around with them. The first thing we should understand is that the controls from the project primitive will affect only the shape of that primitive. Similarly, the controls from the bounding box of our object will control the interaction between the primitive and our main object.

For example, you can use the Gizmo 3D to proportionally scale the primitive. That is clearly only affecting the size of the primitive.

An easier way to explain that threshold is with percentages:
BB = Bounding Box of the primitive shape
> 50% BB outside the main objects bounding box = Project inwards
< 50% BB outside the main objects bounding box = Project outwards
= 50% BB outside/inside the main objects bounding box = Weird inverted normals (avoid that).

Now in terms of the controls (cones), I’ll do my best to explain them individually, but I think the best way to learn how they work is by playing around with them. The first thing we should understand is that the controls from the project primitive will affect only the shape of that primitive. Similarly, the controls from the bounding box of our object will control the interaction between the primitive and our main object.

For example, you can use the Gizmo 3D to proportionally scale the primitive. That is clearly only affecting the size of the primitive.

Next one up, is the orange cone, this one is the Maximum displacement. With this control at 1 (the default value) we can tell ZBrush “Hey, we want a ‘full projection’ of the primitive into our sphere”. If we change that value to 0, we are quite literally projecting the primitive with 0 strength so there is no change in the volume of our main object.

Let’s leave it at 1.

The Pink cone is the overall opacity. Similar to what we did with the Z axis, but with this cone, we can control the opacity of X, Y, and Z in at the same time. Be careful, because this cone, allows you to go into negative values, so it will look like you are inverting the effect but it will flip the polygons. Finally, the light blue cone at the end, allows you to assign polygroups to the affected area by the projected primitive, leaving it at 0, no new polygroup will be added. If you move it to 1, every time you click on ANY CONE, to edit the primitive or the original mesh, ZBrush will update the effect of the project primitive with a new polygroup… also the reason why in this guide the colours keep changing

The white and RGB cones on the opposite corner, are to activate symmetry in the X(R), Y(G) and Z(B) axis. The white cone is radial symmetry so you can rapidly achieve some very cool designs just using this deformer.

Hopefully, this initial explanation is clear because things are about to get real from this point…

The next thing we need to get used to is, that the primitives are not necessarily a ‘definite shape’. I’ve been calling the projected primitive a sphere BUT, that ‘sphere’ it is driven by a function. Let’s keep things simple and say that that ‘sphere’ is nothing more than the middle point (value of 0.5) between two volumes.

Let me draw your attention to our first cone control of the actual primitive shape: The pink cone or Blend.

This control might look similar to the opacity cone we discussed earlier but is very different. Remember that we have two set of ‘cones’: The ones that control the shape of the primitive itself and the ones that control the interaction or effect on the main shape. The Blend controls how the primitive shape is mixed with the main object. Let’s set this value to 0 so that there is NO blending between primitive and main object.

So, if we have the Blend control at 0, the opacity cone (pink) at 1 and the Maximum displacement (orange) at 1, we can safely assume that we are seeing the real shape of the primitive.

Now, here is a good opportunity to see the difference between ‘Blend’ and ‘Opacity’. Go ahead and change the Opacity value (pink cone) and this will show you how much of the ‘real shape of the primitive’ is shown in our model.

The next cone is the Modifier control (orange). If you hover over this cone, it says ‘Modifier = 0.5’, this is the value that represents the sphere in this example.

Now, because we are seeing the ‘real shape’ of the primitive (no blending, opacity at 1, displacement at 1) it will be very easy to see the effect of the modifier. If we push it all the way to 0, we basically have an octahedron. If we change the Modifier value to 1, then the function describes the volume of a cube:

I hope you can already see the value and the potential of this tool. If you still are not convinced, remember that this is a projection. We are modifying the shape of the main object on the fly…

Quick tip: Hold the ‘Shift Key’ on your keyboard when moving the cones to snap the values to ’rounded’ numbers (0, 0.5, 1, etc).

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Set the modifier back to 0.5 (to the value that gives us the sphere), and let’s move on to finish with the advanced controls so that you can actually see the benefits of this tool in action. The next cone is the Yellow one, this one is the Primitive Type. Currently is at 1 and that is the shape what we’ve been working with, but if we move it to ‘2’ things get more interesting.

Now we have 2 orange cones or modifier controls. They allow us to change the value of a quadratic function and therefore changing the volume of the primitive. I’ll try to explain this attribute the best I can base on my very basic understanding of it.

At the moment, the Primitive Type 2 looks very much like a Cylinder. But playing with the values of the two modifiers, we can quickly turn that into a sphere, an octahedron, a cube, etc.

Make sure the second modifier is at 0, and then use the first modifier to change between shapes.

Now let’s set the first modifier to 0 and play with the second one to see what alternative volumes are described by the function.

Great, now let’s see what happens when we set both modifiers to their middle points with values of 0.5

We are back to our sphere. There are two more primitives you can play with, set the Primitive Type control to 3 and play with the modifiers to create a cone for example, or with Primitive Type 4 you can create a sharp ring over the sphere:

Now we have 4 more things to go over, but I think the hard ones are out of the way. The next control is the first Blue cone, this is the Primitive axis which simply changes the orientation of the primitive shape. As you change the value (moving the cone inwards), you’ll see how the primitive changes orientation and the cone itself updates to the RGB colour for the respective XYZ axis.

Then we have the purple cone for ‘New surface’. Change its value to 1 or more. You’ll see that there are fewer cones to control it, but this is now a ‘new surface’ not an object deforming the main shape. You can think about this process as inserting (like inserting objects from an IMM brush) a new primitive to your object, therefore there are no blending or opacity sliders for example.

Finally, the white cone is to ‘Accept’. This control is part of what makes this deformer so powerful. With the white cone, you can ‘accept’ or ‘lock-in’ the primitive object and add a new primitive (or a new surface if you also use the purple cone) to keep modifying the shape of your main object (as many times as you want).

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Let’s address those little withe points that are within the Gizmo 3D… Those white dots are fantastic because they allow you to flatten or ‘clip’ the project primitive surface and control the effect even further. simply click and drag them to see the ‘clipping’ effect. You can also hold ‘Shift” while dragging any white dot to maintain symmetry on the selected axis.

Ok, I think that covers the controls and the features of this awesome new deformer. So far we haven’t created anything exciting but I think is better to have a full understanding of what the tool can do. Knowing the basics will make it easier for you to explore all the possibilities.

Here is a timelapse of a rough Sci-fi helmet I created using just this Project Primitive deformer. This should give you an idea of how powerful this tool can be: