Scalers

In this tutorial, you will learn about scalers. Specifically, you’ll learn:

• What scalers are, 
• How they work,
• How to add a scaler to a mesh product or make a scaler-only product, 
• And a couple of principles you need to keep in mind during this process.

Note: This article assumes that you have watched/read the tutorial about Skeleton first. If you haven’t, it’s highly recommended for you to watch it beforehand for easier understanding.

First, what is a scaler? Scalers allow you to resize and manipulate the width, length, and height of a mesh. Scalers can only be applied to avatars and avatar clothing products, meaning they cannot be used for furniture. 

So, how do scalers work? Let’s say we want to apply scalers to an avatar. An avatar consists of bones, which affect the mesh that covers them. Scalers can be applied to one or more bones and scale the vertices weighted to them and change the shape of the mesh. This means you can make any body part bigger or smaller, longer or shorter, thicker or slimmer. You can also make the scalers apply to accessories whose skeletons happen to be attached to the bone. This means that you can scale your mesh without worrying about whether accessories and hair products will be broken. It all just works!

Then, how do you add a scaler to a mesh product? Let’s try scaling a head. 

1. Open IMVU Studio 
2. Search for the head you want to scale
3. Click “Derive”
4. Go to the “Scale” section on the left column
5. Adjust the scale value by typing in numbers in the text fields. 

In the three-dimensions, there are X axis, Y axis, and Z axis. 

Note: On IMVU Studio, the X, Y, and Z are relative to the bone, not world space. In other words, how the X and Y axes are oriented (if they move left to right or front to back) varies depending on the bone. However, the Z axis is always along the length of the bone.

The scale value is a multiplier so a scale of 2,2,2 scales the size of the mesh by 2x in the X,Y,Z. Likewise, a scale of 0.5, 0.5, 0.5 scales the size of the mesh by half the original size. These three numbers don’t have to be the same, and you can always be creative with them.

As mentioned earlier, you can adjust body parts AND clothing meshes. But how do you make a “scaler-only product”? Scaler-only products, or scalers, are a pure form of scaler you can layer on your avatar and alter specific body parts so the proportion and overall shape of the body fit your aesthetic.

You can make a scaler by deriving from “Empty Female Clothing”. (Note: If you want a scaler for your male avatar, you should derive from “Empty Male Clothing”.)

1. Click “Create” on the top right and locate Empty Female Top
2. Click and derive from its parent item “Empty Female Clothing”
3. Once the item loads, go to the “Scaler” section on the left column
4. Click on the plus sign to add a bone you want to scale

Now, there are two more things you need to know in order to proceed from here. First, bone names and second, skeletal hierarchy. Each and every body part of an IMVU avatar has a specific bone name. You have to use this exact name when scaling so that Studio can identify that particular body part you want and scale it properly. 

Skeletal hierarchy is basically an organized map of these body parts that show their hierarchy. The ones on top parent the ones below them. For example, the left hip is the parent bone of the left thigh. So, the left thigh is the child bone, and it’s also the parent bone of the left calf. It’s important to keep this hierarchy in mind, because when you add a scaler to a bone with child bones, those child bones also get scaled.

Let’s try making a scaler for thicker legs. The node is where you can input the bone name by either selecting from the drop-down list, or just typing in it directly. (Note: the bone name is capital-sensitive.) 

1. Select “lfHip”
2. Input 1.3 (or any number that is larger than 1) for the X and Y axis. (Note: Doing the same for the Z axis will lengthen the leg and make it skinnier.)
3. Hit preview

You will notice how even though you chose the left “hip”, it doesn’t only thicken the hip part, but also its entire child bones, including the left thigh, calf, and even the foot and toes. You can add the same scaler for the right leg for a balanced look. If you want only the thighs to be thicker, but not the hips, you can select “lfThigh” and “rtThigh” as nodes instead.

But what if you don’t want the child bones to be affected? You can add a scaler to the child bone and apply a value that is half the value of the parent scaler. So, you basically scale them twice. Let’s say you don’t want the feet to be thicker. You add a bone scale for “lfFoot” and a bone scale for “rtFoot” and input half the value you put in for the thighs. Since we put 1.3 in the earlier example, we’re going to put 0.65. Hit preview, and you’ll see the result. You might notice that since the scale values are different, the shape of the mesh gets a little jagged. But no worries, you can always play with the numbers to make the shape more natural.