Illustrator blend tool is where ? It can be used to blend two (or more) paths / objects in Adobe Illustrator and is found via the Illustrator toolbar.
To mix between paths / objects, create some paths or use existing paths. Select the tool. Select paths (though not required). Click center points or segments or points of those paths to generate the effect between the paths. You will then see you default combination between the paths.
Create a number of paths (more than 2). Select it and click on path one, click on path 2, click on path 3, click on path 4 etc. This can be repeated with a number of paths (though I have no idea if there are a limit). Again, use the direct selection to manipulate the size, points etc of the component paths. You can also edit them in isolation mode by double clicking the path and then tweaking the design using a variety of features within the application.
Double click the icon to display the options or when selected, press return should also work. Set the spacing method. Set to specified steps and set the number of steps and set orientation (to path etc) and set preview to ON. Or use the smooth (must admit, rarely use that one) and also the spacing option is available so if you want to combine between objects such as 1cm gap then use that. The key thing to remember the effect is always live and can be changed at any point so if you decide to use the spacing option instead of the steps then you can by double clicking the icon with the object selected. If you have multiple effects, they can all have different options. The same effect with multiple items will all have the same color combo between them. The design can still be manipulated as a normal path such as rotated etc. Also the spacing, you may want your paths to be 45pt apart
You can use it to distribute items between two paths, you need a circle placed at 100 pt 200pt etc then set the distance to 100pt between two circle objects.
Once you have applied the effect, you can still alter the paths involved in the effect such as changing the shape of the paths or perhaps changing the color of the paths and that can be done by selecting the path using the direct selection and then changing the color or shape etc for that path or perhaps removing or adding points etc. Go to the direct selection. Select the first or second etc path in the object. Change the color via the fill color (or stroke). Go to the object menu and transform and rotate etc (to rotate one of the paths). Add a point to one of the paths by using the pen. Use the direct selection and manipulate the new point or others in the first path. You will now notice that the result will change as you change the color and also the points etc. Points can be added to one of the strokes such as via the curvature.
There is also a spine (not the paths used but the line between the paths) and you can also use the direct selection to select that spine path and then shift the spine path and distort the spine from the initial straight line. You can also then use the curvature or the anchor point to manipulate that spine. You can then use it to create some truly unique paths with the effect and it is still all live and the steps and smooth color etc can still be changed
Create a combination of paths. Select that object. Go to the add anchor point and add a point in the center of the blend to the spine that runs between the first path and second. Use the direct selection to select that center point of the object (select only that point, not the end points), drag point to re-align the spine. Go to the curvature and double click the center point (to turn it into a smooth point).
There are also a number of menu commands which can be found via the object menu and blend. Select paths and use the Make, Release, options, Expand, Replace spine, Reverse spine, Reverse front to back commands. The spine ones are really super useful but the others can be done elsewhere such as the standard expand.
All the menu commands are super useful, The replace spine definitely. Select the object and also select an open path such as a spiral and then use the replace command. Or select a circle and the object and then use the replace and the design will then be added to that to create truly wow circular and spiral or any other shape designs. Of course, more abstract designs can be used as well.
The "reverse spine" command swaps the spine around so if you have a red large path at the start of the object and a small blue path at the end, the reverse spine command will then place the blue at the start and the red at the end (and everything in between is also reversed).
The "release" command just removes the effect - which is the least useful feature perhaps as you can always just undo or delete it (but the release just leaves you with the original paths). Expand - expands the it to a normal set of paths.
You can add the results into the CC libraries as well as using them as a great source for symbols etc by adding the artwork to the symbols panel and then you can use the artwork as a great source of designs using the symbol sprayer. Combine paths as mentioned above and simply drag into the CC libraries panel and the resources can then be used in future projects as well as in other applications such as After Effects and Premiere
You can use the paths in the new feature 'repeat' but you need to expand first via the object menu. You can then use the objects with the new radial as well as grid and mirror feature to create all kinds of amazing designs in the most recent versions of the application. You can modify the shapes, you can re-color etc but the design is sadly not live.
You can select the object and then go to the object menu and envelope distort and make with warp and you can warp the object in all kinds of ways. You can create some truly weird mesh warps