In this tutorial we will explain what a transformation is and how these can be performed in Model Lab.
A transformation is a function or operation that that takes a point as input and outputs a new point. When talking about 3D-models the points that are to be transformed are called vertices.
The 3 basic transformations are:
Basic Concepts and User Interface Explanation
The pivot is simply a point in space, also referred to as pivot point. You can think of the pivot point as the local origin of the model in relation to the space origin.
It is basically the same thing as the position of the model with an important difference. If you change the position of the pivot point it does not move the geometry in the model, you only move the local origin. The geometry in the model is only moved when a transformation operation (scale, rotate or translate/position) is executed.
You should also note that the pivot point that remains fixed (does not move) during scaling and rotation. You can input your own values to define the pivot point, but usually you are better off using the quick buttons, Lower left and Center.
The scale simply defines the dimensions of the model. You may adjust the scale of the loaded model by changing the slider or input field to the right of the slider. The value to the right can be thought of as a magnifier.
For instance, by setting it to 2, you will double the size of the model. By setting it to 0.1 you will reduce the size of the model to a tenth of the original size. You can also change the scale by inputting a desired width, depth or height. The values in parenthesis display the original size.
If you know you have a lot of models that need to be downsized using the same scale, you can use the remember scale option.
It will automatically change the scale of the model during import. All the scaling operations are uniform which means that if you for instance double the width value, the depth and height values will also be doubled.
The smaller square is in lengths of 0.25 meters.
A larger square, made of 4 smaller squares is 1 meter.
Here you can input the position of the model, also known as the translation.
There are some quick ways that can come in handy when you want to position you model quickly, the Position Picker and Place on floor.
The Position Picker shows 2 arrows within 9 squares, and an XY axes button.
The axes are marked red, green and blue, which corresponds to X, Y and Z. So as long as you remember RGB, you will know if you are changing X, Y or Z.
The 2 arrows symbolizes the 2 axes of the drawing, which is now X and Y.
The 9 squares can be clicked to place the model in relation with the origin point of the space(not the pivot point).
Clicking on the XY axes button will change the 2 axes and will show you either XY, XZ, or YZ. This determines which 2 axes the region picker buttons are working on:
Place on floor will move the model so that its pivot point is on the floor:
Used to change the rotation of the model. Keep in mind that the position of the pivot point affects the outcome of a rotate operation.
Fixing the Transformation Issues
- Download and load the Fika chair (transformation issues).cmsym file found at the top of this article.
- We'll begin by adjusting the scale.
Currently the width is 22m. A chair is more likely to be around 0.5m in width.
Input 0.5m as the width and press Enter.
Notice how the depth and height are uniformly scaled.
Now let's make the chair stand upright, we need to rotate the model -90 degrees around the X-axis.
Input -90 as the rotation for X. Model Lab will automatically interpret this as 270 degrees which will result in the same rotation as rotating -90 degrees.
The chair is still floating in the air. Don’t worry, this can be easily fixed.
Set the pivot point to the lower left corner of the model by clicking Lower left under the Pivot.
Under Position click Place on Floor to lower down the chair to the floor level.
Finally, in the Region Picker, make sure the XY-axes are selected, then click on the top right square.
The fixed model should now look like this:
That’s it! Now you should know:
- What a transformation is.
- What a pivot point is.
- How scale, position and rotate operations can be performed in Model Lab.