Learn the Very Basics of syFlex

In this tutorial from Syflex, we will go over the basics, by... Hanging laundry: Turning a simple plane into a syCloth, applying Gravity and Damp forces onto it, pinning it to the string using one of the syFlex constraints, and lastly, blowing some wind, so it really behaves.

This tutoriel provides a nice overview of the basics of syFlex for new users, or, if you don't have syFlex yet, look here to get a sense of just how simple and powerful it is.

We used Maya 6.0 for this tutorial, and we started by constructing a string to hang the laundry on. You can build your own string, or download this Maya Scene, where you will find a ready-made string, already simulated, complete with a pair of clips (note).

01. CREATE YOUR CLOTH SHAPE, make a poly mesh:

creating the shape

Modeling and positioning the poly shape

Any poly mesh can become a syCloth. Here, we created a simple plane to become a sheet of cloth. Our plane is the default Maya 1x1 plane, subdivided by 30 width and 40 height, and scaled a bit so it is more rectangular. We recommend that you follow those dimensions, so our parameters will work for you.

Translate and rotate your plane to the position you want to start the animation from. It is better to do all the translation before you turn it into a syCloth. We started the cloth at 90 degrees to its "hanged" position to have more drama in the animation.

02. CREATE CLOTH, turn your shape into a syCloth:

Syflex Menu

This is the whole syFlex menu

Select your plane, and turn it into a syCloth, by calling:

Syflex > Cloth > Create Cloth

Take a look at the syCloth set of attributes; Select your syCloth, either by pointing at it in the 3D view, or in the Outliner (either the output shape node, or the syCloth node) and examine the available attributes in the Channel Box. More attributes are available in the Attribute Editor window.

In this tutorial, we are focusing on two attributes: Mass Density and Spring Stiffness.

03. GIVE YOUR SYCLOTH CHARACTER, define attributes:


SyCloth attributes

The Mass Density is the mass of a 1x1 surface unit of the cloth. Together with the Gravity force (coming next) it gives a feel of weight to the cloth. The Mass Density also influences the speed of the simulation; The higher it is, the faster the simulation.

The Spring Stiff attribute controls the stiffness of the springs a syCloth consists of. There are three Spring Stiff attributes, one for each type of springs; Stretching, Shearing and Bending. Having control over the stiffness of each type of springs independently, allows a range of options for defining the cloth characteristics.

The Stretch Stiff value is usually higher than that of the Shearing, and the Shearing value is higher than the Bending. The Spring Damp value needs to be adjusted to control unwanted vibrations. Follow the values provided here to start with. After we pin the cloth to the string, you will be able to start playing with those values, and conveniently see how they affect the animation.

04. CREATE WEIGHT, add Gravity and global Damping:


SyFlex' Forces menu


Gravity attributes


Global Dump attributes

The Gravity, like all the rest of the forces and constraints in syFlex, obeys the normal laws of physics. It is always possible to make exact measurements and calculations (for example, find the Mass Density of a real cloth, and use the value in your scene). SyFlex artists, however, usually choose to work intuitively (go figure).

No matter which way you work, it is useful to first understand the concept of each force, and especially, how each parameter influences the animation.

Select your syCloth, and apply Gravity and Damping onto it:

Syflex > Forces > Create Gravity
Define the level of Gravity in the attributes window.

Select your syCloth, and apply Damping onto it:

Syflex > Forces > Create Damp

Define the level of Gravity in the Gravity attributes window.
Select the syCloth, and apply Damping onto it:

Syflex > Forces > Create Damp

Define the level of global Damp in the Damp attributes window. Damping helps you get rid of vibrations and noise created by the motion, but it also slows down the animation. Note how low the value is in our tutorial.

You can play the animation now and see your cloth following the law of Gravity, computed in realtime. If you don't have SyFlex yet, you can watch what happens in this little movie.

05. PIN YOUR CLOTH TO THE STRING, add a constraint:


Selecting the vertices to be pined and the String


SyFlex' Constraints menu

Select the corner vertices of the sheet, and the string, and call:

Syflex > Constraints > Pin

Run the animation, or watch this little movie...

Cool, no?

What's really cool, is that the animation is still computed in realtime. Now it's time to start playing with the Spring Stiff, Mass Density, Gravity and Damp parameters, and discover how to make the cloth behave in different ways.

You can also try creating sheets in different sizes. The attributes values will have to change proportionally to the change in dimensions.

Try also animating sheets in different resolutions. You will see that the higher the resolution is, the more wrinkles are created, while it also makes the simulation slower.

06. BLOW SOME WIND, add another force:


Wind Attributes

Just for fun, we also added wind.

Select the syCloth, and call:

Syflex > Forces > Wind

The wind is a little tricky to control. Start by entering the values suggested here.

Run the animation (yes, we have another little movie, 82 KB...)
Add your texture...
Keep playing!...

Note: The clips we prepared for this tutorial are simulated using the syFlex' Pin contraint. In the next version of syFlex, there will be a new "Button" force, which will solve such a requierment, and all other "button situations".

In-depth information about every aspect of syFlex, including the elements used in this tutorial, are available in the software documentation. If you have any additional questions, do contact us at: users@syflex.biz


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