[Part-1] F-Curves & Graph Editor in Blender | Hands-on Examples | Interpolation | Eevee & Cycles

in this tutorial we will discuss what is an f curve in blender and how to use it in an animation whenever we add any motion to an object or we keyframe any of its properties we may not notice it always but behind the scenes blender adds an f curve for every such key field this is the foundation level tutorial in which we will learn how to edit these curves and how to manipulate the animation behavior through this so let us start with a blank new file we'll add some motion to this default cube the name f curve comes from ferguson's parametric curves that are used in airfall design and interpolation so we will move this cube along the x-axis we are currently at frame number one let us insert a keyframe for the current x value which is zero we'll then go to frame number 75 and we have to move the cube in this direction let us say we move it by 15 units we have to keyframe this value as well now if you play the animation from the beginning it follows a slow start and then also a slow ending in a smooth fashion throughout the journey the movement is not linear it's like a train that starts slowly from one station then picks up some speed and then slows down again at the next station we can also verify it manually how the change actually happens to its location values at each frame number and how it interpolates we are covering a distance of 15 units in 75 frames that means one unit in each five frames currently we are at frame number one and the x location is zero if we go to frame number five we expect to move by one unit but it is just a fraction of that and if we go to frame number 10 we should be moving by two units but we did not go even one unit here but if you go to frame number 40 we are in the middle of the section and we have covered more than eight units this means it has picked up the speed sufficiently in between and it will again slow down towards the end so this kind of slow down or the easing of a movement is controlled by an interpolation technique which is nothing but the f curve and to see the f curve you have to switch over to the graph editor from this option so on the left hand side panel in this screen we have a list of all the objects present in the scene like we have the default cube here and under the object transformation group we have an entry for the x location key which is represented by this red line let us zoom out and reposition our graph as you can see this curve is not really linear it has a flat slope in the very beginning and also at the end that is why the cube is moving slowly at these two points you can easily change this behavior just right click on this and change this interpolation mode say we choose linear now the curve is a straight line and the cube will follow this let us go back to the 3d viewport if you now start the animation from the beginning you'll see that the easing effects are gone at the two ends it starts and stops just abruptly following a perfectly linear motion it is probably also not very realistic because now it has a constant velocity throughout the entire duration an easy start and a slow stop may look better but there are more ways to customize it exactly as your scene demands we'll experiment with some other variations so let us first make some room for the graph editor to be displayed alongside our viewport and we also need the timeline editor so we can split this screen once more and keep the timeline editor at the bottom of our window we have to now change this editor type to graph editor so we can see the interpolation here and we have our viewport at the top we can see the motion of the object real time as we make changes to our graph the way it works is it has got two panels on the left side we have a list of all the objects having keyframes along with their key fields whatever field we keyframe here will appear over here and here we have the actual graph or the f curve for the selected key field that we can manipulate if we deselect everything in the viewport this list will show blank it won't show any item at all we have to first select an object in our scene and the object must have a keyframe like we have a keyframe on the x location so its graph is here now if we keyframe this y location here it will appear in this list of key fields and its graph is shown in this green color so anything that you keyframe will have an f curve let us remove this for the time being so you already know that the type of this curve can be changed from the right menu by changing this interpolation mode to any of these defined functions the object transformation will now follow this pattern and when you apply this change it is applied between this keyframe and the next keyframe right now both the points are selected let us deselect them and select only this key point if you now right click and change the interpolation mode to say linear you won't see any change in the curve that is because this is the last key point there is no next key for the change to take effect however if you select this key point instead and make the same change over here the curve will change immediately let us insert a third key point we have the first key at frame number one the next key is at 75 and the object is here let us go to frame number 150 and we'll move the object back to the origin so its x location should be 0 and we'll keyframe it now we got three key points for this property so let us change only this section of the curve to do that you have to select the second key point then right click and select any function say we take sinusoidal so this part is now linear and this part is following a sinusoidal mode if you want to customize it further manually you have to use the bezier mode so press a on your keyboard to select all the key points for this selected property then right click and in the interpolation mode select this bezier option we have now got these handles for each of the key points and we can manipulate them in whatever way we like let's say we want to change this to a fast start so we have to move this handle upward to create a vertically steep curve then it becomes flat towards the end of this section something that happens in case of an explosion a quick start and a slow end game if we now run the simulation you can see how the cube follows the desired motion profile and then it also comes back following this part of the curve and in case we want to start it slow we have to just move this handle and make it flat or horizontal and say we want to then end the motion very fast so we have to move this handle upward now it will start slowly and end like a falling object let us run it and verify so the object starts slowly then it follows this profile in the return journey and ends very fast like that so this way you can manually edit this curve and create a motion profile that suits your requirement let us modify it little more please remember we have taken an example where the object's motion is involved but f curve is applicable everywhere let us make this end flat this time if you animate any property be it the color or the density or any such field you will get an f curve in the graph editor and you can manipulate them in the same way so let us make this middle portion sharp so that the object bounces back quickly when it reaches this end of the motion path we'll now play the animation and verify it so it starts slowly then it takes a quick turn and again slows down and finally stops at the origin so far we have learned the basics of editing of an f curve and we'll now examine how to add another curve over here for a second animated property let us take this y location and animate it we will add some random motion or vibration in the y dimension while the object moves along its x dimension so it will vibrate and move along its path and to do that we have to add a keyframe for its y location and we get a new entry here if you select it you'll get this green line which is a constant value but we'll add a vibration or a noise to this line through modifiers so press n on your keyboard or just click on the small arrow to display this side panel then go to the modifiers tab open this list and add one noise modifier from here you will see that some noise is now added to the existing straight line for the y location curve but this is not very strong so let us increase its strength to five and press n to hide this panel so we can clearly see the vibrating motion added in the y dimension now if you go to the start and play the animation you can see how the cube is vibrating while it still moves in the x dimension following its original path both are playing together it's an easy technique to add vibration to any motion but don't overuse it we have exaggerated it for the tutorial you can use it in a subtle way for a realistic effect you can also notice that it stops moving after completing one round in the x dimension this is correct because we have added only three key points for the x dimension motion and it stops right after that but what if you want the cube to move back and forth continuously until the end of the animation we can do that easily let us first increase our scene length maybe to one thousand we don't need to add more key points to create a continuous play we can just add a modifier for this x location field so right click on this and go to this extrapolation mode and select this cyclic option as a result blender will add a repetition of the same pattern or the same key points for this curve if you ever need to remove it just right click here and in the extrapolation select this clear cyclic internally what it does is it adds a cycles modifier so while this x location field is selected press n to bring this side panel you can see that a cycles modifier is added to this you can also add it manually or you can use the shortcut from the right click menu so with that setup let us run the animation once again the cube will follow the desired motion the only difference this time will be it won't stop at the end of one cycle it will resume the journey in the same fashion in a repetitive sequence as long as the scene runs you can also control how many times it repeats in fact this is just a foundation tutorial on f curve we'll discuss about more advanced topics in the next part but i hope you got the basic concepts behind the graph editor and you learned how to work with this thanks for watching and don't forget to subscribe to this channel

Channel: 5 Minutes Blender

Views: 10,854

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Id: PlThnja6KmU

Length: 11min 0sec (660 seconds)

Published: Tue Oct 12 2021