One of the most powerful uses of a Fixed Resource Process Flow is to unify a set of machines and operators as a reusable entity. For example, many factories have several production lines. Simulation modelers often wonder what would happen if they could either open or close more production lines. If you were to open a new line, would the increased output be worth the cost? Or if you were to close a line, would the factory still be able to meet demand? These are the kinds of questions modelers often ask, and by using a Fixed Resource Process Flow, you can answer this question. This article demonstrates how to use a Fixed Resource Process Flow (or FR Flow) to coordinate several machines and operators as a single entity. The example model represents a staging area, where product is staged before being loaded on to a truck. However, most of the concepts that are discussed could be used in any Fixed Resource Process Flow. Creating a Collection of Objects When you set out to build a reusable FR Flow, it is usually best to start by making a single instance of the entity you want to replicate. Often, it is convenient to build that entity on a Plane. When you drag an object in to a Plane, it is owned by the Plane, which makes the Plane a natural collection. If you copy and then paste the Plane, the copy will have all the same objects as the original Plane. This makes it very easy to make another instance of your entity: just copy and paste the first. If the Plane is attached to an FR Flow, then the copy will also be attached to the same Flow, and will then behave the exact same way. In the example model, you will find a Plane with a processor, five queues, and two operators. This makes up a single staging area. The Plane itself is attached to the FR Flow, meaning an instance of the FR Flow will run for the Plane. It also means the Plane can be referenced by the value current . (You may find it helpful to set the reset position of any operators, especially if they wander off the plane at any point during the model run.) Using Process Flow Variables In order to drive the logic in your entity using an FR Flow, you will need to be able to reference the objects in each entity, so that they will be easily accessible by tokens. For example, if items are processed on Machine A, Machine B, and Machine C, in a production line, then you would want an easy way to reference those machines in each line. This is where Process Flow Variables come in. In the example model, you will find the following Process Flow Variables: Every staging area has a Packer, a Shipper, and a Palletizer, each referenced using the node command. Remember that current is the instance object, which is the Plane. Once these variables are in place, you could create an FR Flow like the following: If you ran this model with the Plane shown previously (complete with correctly named objects) and this flow with the shown variables, then the Packer operator would travel to the Palletizer. If you then copied the Plane, you would see that all Packers go to their respective Palletizers, as shown below: Using Variables and Resources Together Sometimes, you may want to adjust the number of operators per line, or even the number of operators in a specific role. To do this, you can again you Process Flow Variables. The sample model includes these variables: The sample model also includes these resources; the properties for the Shipper Resource are shown: Because this resource is Local, it is as if each attached object has its own version of this resource. Because it references a 3D operator, it will make copies of that operator when the model resets. The number of copies it creates will depend on the local value of the ShipperCount variable. To edit the value for a particular instance object, click on that object in the 3D view, and edit the value in the quick properties window. Disabling Entities Often, modelers simply want to "turn off" parts of their model. If that part of the model is controlled by a fixed resource flow, then you can easily accomplish this task. In the example model, you will find the following set of activities: The Areas resource is numeric, and it is global. The Limit Areas activity is configured so that any token that can't acquire the resource immediately goes to the Area Disabled sink. If the token that controls the process dies, then the area for that token is effectively disabled. The example model uses a Process Flow Variable to control how many areas can be active at a time: The Areas resource uses this value to control how many shipping areas are actually active. If this number is smaller than the number of attached objects, then some of the areas won't run. Note that the order the objects are attached in matters. The first attached area will be the first to generate a token in the Init Area source, and so will be the first one to acquire the area. Using Process Flow Variables in the Experimenter/Optimizer Currently, only Global and User Accessible variables can be accessed in the Experimenter. In the sample model, the only variable that can readily be used in an experiment is the TotalAreas variable, which dictates how many areas can be active. This allows the Experimenter or Optimizer to disable lines. To make it possible for the Experimenter or Optimizer to vary the number of Shippers or Packers per Area, the ShipperCount and PackerCount could be changed to Global Variables. You could put labels on the instance object (the Plane) that are read by the variable, like so: Then the experimenter could set the label value on the Plane object that is attached to the FR Flow. The Experimenter would set the label, which would affect the value of the Variable, which would affect how many copies of the Packer were created by the Packer resource. You could do the same for the ShipperCount variable. Sample Model The attached model (usingfixedresources-6.fsm) provides a working model that can demonstrate the principles in this article. It comes with only one Plane object attached to the FR Flow. Here are some things to try with the model: Reset and run the model to see how it behaves with a single area, where that single area has only one Packer and one Shipper. Create a copy (use copy/paste) of the Plane. Reset and run the model again to see how a second area is automatically driven by the same flow. You may need to adjust the TotalAreas variable if the second doesn't run. Adjust the number of Packers and Shippers (using the Process Flow Variables) on each Plane. Reset and run the model to see how adding more packers and shippers affects it. Create many copies of the first Plane (it is best to set the PackerCount and ShipperCount to 1 before copying). Reset and run the model, to observe the effect. Add or remove some staging areas (queues) to an Area. This model handles those changes as well (in the Put Stations On List part of the flow). Try to set up an experiment or optimization, that varies how many lines are active, and how many Packers and Shippers are in each. In general, play around with the sample model, or try this technique on your own. Other Applications This technique can be used to create production/packaging lines, complex machines, or any conglomerate of Fixed Resources and Task Executers. If you follow the methods outlined in this article, you will be able to create additional instances of complicated custom objects with ease. You will also be able to configure your model for use with the experimenter or optimizer.

Using Mixamo Fuse, Mixamo, and (optionally) 3ds Max, you can create animated characters for use with FlexSim. For modifying the existing operators' animations, see Adding More People Animations From Mixamo Character Creation You can customize a character’s look using Mixamo Fuse: After creating the character, you can save your character as a .fuse file in case you want to edit it again later in Mixamo Fuse. Character Rigging From Mixamo Fuse, you can press the Animate button in the upper-right corner to upload the character to Mixamo’s website to apply animations. You will need to log in with a Mixamo account. You will be presented with the Mixamo Auto-Rigger. After a few moments, your character will appear in a view with a default animation applied. Choose whether to enable facial blendshapes and select the appropriate level of detail for the skeleton, such as 2 Chain Fingers, and then press Update Rig. The auto-rigger will reapply and the view will be updated with the newly rigged character. If the settings are good for your needs, press the Finish button. Character Animating Once the character is rigged, you can select it on the Mixamo website and press Find Animations to find animations to apply to the character. You can search for animations and add them to packs. For each animation, you can adjust various parameters to fit your character to that animation better. Exporting the Character and Animations Once you have applied and customized animations for your character, you can add them to the Cart and checkout in order to have them available for download. After checking out, you can select an animation or animation pack to download on the My Animations page. You can apply the same animation sets to different characters using the Change Character button after selecting the animation set. Press the Queue Download button to tell the Mixamo server to create the files for download. You want to use the FBX format so that we can edit it with 3ds Max. The pose can probably be T-Pose or Original because the Original is probably a T-Pose anyway. I use 30 Frames per Second for consistency and ease of timing animations. Keyframe Reduction didn’t seem to do anything in my tests, and you can do it yourself with more control in 3ds Max so I use “none.” If you exported multiple animations, the output will contain one fbx file that is the character shape and several other fbx files that contain only animation data for each animation. (Update) Important Note: Starting with FlexSim 2017 Update 2, the rest of the steps in this document are no longer necessary. FlexSim 17.2 added support for embedded textures, specular maps, and gloss maps that fix the material issues directly without modification in 3ds Max. FlexSim 17.2 also added support for assigning animations to a shape from multiple files, so you can import the mixamo output files directly without having to merge all the animations into a single file. The following steps can be used if you want to optimize or otherwise modify the shape files, but are no longer required. Preparing the Character using 3ds Max Import the character shape .fbx file into 3ds Max and save the file as a .max file. You will want to resave as a .max file at different points with different file names as you progress so that you can easily revert back to a previously known working point if something messes up. The FBX Import window will show you lots of options you can modify. The defaults seemed to work fine. I tried messing with the “Units” scale factor and file unit conversions, but I was unable to find any options that improved the scaling in FlexSim. Ultimately, I found it best to just use Automatic and sort out the units myself using FlexSim’s shape factors. Export the file as fbx and bring it into FlexSim to see how it looks. Again, the default options seem to work fine. In FlexSim, the size will probably be 100x too big (no matter what “unit conversion” options I seemed to set in the import/export options). Resize the character to be 100x smaller. Fixing the Materials in 3ds Max When you first bring in a Mixamo Fuse character into FlexSim, it will probably look shiny and dark. That can be fixed in 3ds Max. Open the Material Editor using the button Double-click each material in the list of Scene Materials on the left to add it to the middle view for editing. Press the “Lay Out All – Vertical” button to arrange the nodes nicely in the middle view. When you imported the .fbx file, 3ds Max should have automatically unpacked its textures into a directory called CharacterFileName.fbm. When you double-click on a texture node in the Material Editor view, you should be able to see and edit the path where it is referencing each texture in the Material Parameter Editor pane on the right. Removing the shininess Each material has Ambient, Diffuse and Specular colors, in addition to any textures that are mapped to various channels. The operator is shiny everywhere because each material’s Specular color is set to White and their specular maps are mostly black. Since FlexSim doesn’t currently read specular maps and gloss maps, the white specular color is being applied everywhere instead of the black color from the specular maps. To fix it, click each specular map and gloss map in the center view and delete them with the Delete key. Then double-click on each main material and set its specular color to black to turn off the shininess. Save the .max file with a new name, and re-export the .fbx file to test it in FlexSim. The shininess should be gone. Brightening the darkness FlexSim uses Assimp to read fbx files. Assimp’s fbx importer is setting a default Ambient color value of dark gray to the materials instead of leaving it off. This is why the character looks darker than he should. To fix it, we can simply specify an ambient color of white on each material. For each material, set the ambient color to white and check the Ambient Color box under Maps: Save the .max file with a new name, and re-export the .fbx file to test it in FlexSim. The darkness should be fixed. Setting local texture paths Based on the procedure above, the texture paths are likely to be absolute paths when you export the fbx file. You can fix that by saving the .max file, the .fbx file, and the textures all in the same directory. In Windows Explorer, copy all the useful textures from the CharacterName.fbm directory into the same directory where you have been exporting the .fbx file. Then also save your .max to that same directory. Once everything is in the same directory, you can reselect the texture file paths for each material so that they are pointing at these files instead of the other files. Then, when you export the fbx file, each texture’s path will be relative so you can copy all the necessary files onto any computer and use them correctly. After changing all the materials, export the fbx file again. You should be able to copy the fbx file and all its textures into a directory on a different machine and have them display properly. Save your .max file with all the updated materials. Making part of the object change color To make a material show the FlexSim color, append _fsclr to its name in 3ds Max: Configuring Animations With the character loaded, you can import the fbx files with just animation data, and it will automatically apply that data to the shape. The slider at the bottom controls the currently applied keyframe. The buttons in the bottom corner play the animation, pause, or step between keyframes. Animation data can be stored beyond the relevant range. You can open the Time Configuration dialog by pressing the button in the bottom corner. In that dialog, you can specify the speed of the playback and set a Start Time (keyframe number) and End Time for the animation you want to see in the viewport when you play. This dialog is only changing the playback options in the software; the actual data outside the specified range is still preserved. You may need to adjust these values as you import/modify/combine animations into one Timeline. Keyframes If you push the button on the top toolbar, it will open the Track View – Curve Editor. You can edit and modify Keyframes through this view. Click in the left pane and press Ctrl-A to select everything in the model. You should see keyframes appear if you have animation data loaded. Sometimes this window doesn’t refresh correctly and you can’t find keyframes. You can try closing it and reopening it, or pressing the and buttons to re-center the view on the keyframes in the configured time range. To edit the animations, you need to be able to see the keyframes in this view. You can drag the current frame by dragging the yellow bar around. You can zoom by scrolling the mouse wheel. Ctrl-mouse wheel will zoom the timeline (X-axis) without zooming the key values (Y-axis). You can select keyframes by dragging a rectangle around them. You can delete selected keyframes with the Delete key. You can move keyframes by dragging them. If you hold Ctrl while dragging them, then it will force the movement to be only along the X-axis and not along the Y-axis so that you don’t actually edit the keyframe’s values, just its time. You can duplicate keyframes by holding Shift and dragging them. Again, holding Ctrl will prevent the new keyframes’ values from shifting by holding the Y-axis still. You can scale keyframes by selecting them, putting the key keyframe indicator on the first keyframe in the selection, picking the menu option Edit > Transform Tools > Scale Keys Tool, and then clicking and dragging on one of the selected keyframes to scale all of the selected keyframes towards the yellow bar. This can be helpful to sync the timing of animations, such as walking empty vs. walking loaded. Preparing Animations for Merging When you load an animation into the file, the Track View – Curve Editor will show you the individual components that have keyframe animations. Different animations may affect different components and the interpolation of transformation information between keyframes may get messed up when you merge different animations that affect different components together into one timeline. To fix this, you can stamp a keyframe at the beginning and end of each animation that stores each component’s position at that point. You can also duplicate the first and the last keyframes to make it easier to specify perfectly-repeating animation clips in FlexSim later. Stamp a keyframe by moving the current frame (yellow line) to the keyframe you want. Then select all within the Track View – Curve Editor to select every component. Finally, press the Set Keys button ( ) at the bottom of the main 3ds Max window to store each component’s value as a keyframe. Duplicate keyframes by holding Shift and dragging them. Also holding Ctrl will prevent the new keyframes’ values from shifting by holding the Y-axis still. Merging Multiple Animations into One File To merge multiple animations into one file, you need the export each of the animations as an animation file (XML Animation File (*.xaf)). Then you can import each of these animations into a specific range of keyframes in the timeline. From the .max file without any animations loaded, import one of the fbx animation files. It will automatically apply it to the shape. Click in the Perspective view and press Ctrl-A to select everything. Then prepare the animation using the information above. Lastly, select the menu option Animation > Save Animation to save the animation as an XML Animation File (*.xaf). Reload the .max file without any animations and repeat this process for each animation you want to merge. Reload the .max file without any animations loaded. Click in the Perspective view and press Ctrl-A to select everything. Then select the menu option Animation > Load Animation to load an animation into the timeline. On the right side of the Load XML Animation File dialog, you can specify the keyframe number at which the animation should be inserted. Do not insert the animation at keyframe 0; make sure that keyframe 0 is the bind T-pose. This will be important later if you want to edit the mesh without breaking the skeletal rigging. You also need to be sure to specify Absolute and not Relative. Select the animation you want to import, specify the keyframe you want to insert at, and then press Load Motion to load the keyframes into the animation. Do this for each animation file you want to merge. Use the Track View – Curve Editor to determine the keyframe at which to insert each subsequent animation. Save your .max file with all the merged animations to a new file. Modifying the Mesh without Breaking the Rigging Sometimes you may want to modify the mesh after you have applied animations. I can’t guarantee that this always works perfectly, but there is a way to make some tweaks even after animations have been applied. Before trying to edit a skinned mesh, be sure to save your work so you can revert back to a clean state if something don’t work correctly. First, you need to be sure that the bind pose is frame 0 and that you are set to frame 0 on the timeline. Second, click on a mesh in the scene and click on the Modifiers tab. You will probably see an Editable Poly with a Skin modifier applied. If you click on the Skin modifier and expand the Advanced Parameters, you will see an Always Deform checkbox. If you clear the Always Deform box, you can then click on the Editable Poly and modify it. You then need to recheck the Always Deform box on the Skin modifier once you are done making edits. Ensure that your animations still work after making edits. In my tests with the operator shape above, when I cleared Always Deform, the mesh moved up slightly. This made the Tops mesh not line up correctly with the Body mesh. To fix that, I cleared and immediately checked Always Deform for each mesh (each mesh then moved up the same amount). Then I verified that the animations still worked and that the arms still lined up correctly with the shirt. Reducing Polygon Count 3ds Max has features for reducing the polygon count of an object. You can apply these modifiers without breaking the rigging by following certain steps. You can display the polygon count of your shape by clicking in the Perspective view and pressing the 7 key on the keyboard. As stated above, before modifying the mesh, clear Always Deform on the Skin modifier. To reduce the polygon count, you can use the ProOptimizer modifier. After clearing Always Deform, click on the Editable Poly and then select ProOptimizer from the Modifier List to add it to the stack between the Editable Poly and the Skin modifiers. In the Optimization Options, be sure to check Keep Textures. Then press the Calculate button. Then you can specify a Vertex % and it will start to remove vertices from your mesh. After applying the ProOptimizer modifier, the normals on your mesh might be messed up. You can recalculate the normals based on a crease angle using the Smooth modifier. Apply the Smooth modifier after the ProOptimizer and before the Skin modifier. Check the Auto Smooth box and specify a Threshold. You can use a value of 89 to get a very smooth surface, only applying a crease to angles that are greater than 89 degrees. After making these changes, be sure to recheck Always Deform on the Skin modifier, and test your animation to make sure the rigging is all still working properly.