Deform Mesh Subtly, randomly across many Objects

Question

There are lots of good Q/A on the Blender Stack exchange about this stuff, but none of it has so far informed my decisions on the best way to do this, so apologies for any redundancy (I did look through all the recommended existing questions before posting!

I'm fairly new to Blender and pushing myself to learn by taking a simple subject and layering on complexity as I slowly begin to grasp Blender's capabilities. My first project to push through was to try to make photo-realistic M&Ms. It's been really fun and SO MANY lights have come on for me! Ok on to it...

My M&Ms start as cubes, get subsurf mod 3x, subsurf is APPLIED, then "Transfrom > To Sphere". After this textures are applied, etc. (This step is probably not the most efficient but I'll work on that eventually).

I then duplicate the Object 5x, apply the five different M&M colors, then duplicate the Objects to create my composition on a plane.

All the M&M mesh objects are perfect squished spheres with no irregularities. This is CLOSE to what I want but real M&Ms have subtle irregularities in shape.

I don't know how to approach:

1. What would be the best way to apply a defomration to a small mesh object with a heavily subdivided topology?

2. If my composition has many of these objects (with many of them having different textures applied) is there a way to apply the subtle deformation to ALL of them?

3. If there is a way to choose a subtle deformation method, then apply to all of them, how then could I randomize it so all the mesh objects don't have the same subtle deformation?

TL;DR

I have a bunch of small heavily subdivided mesh objects with different materials applied. How can I subtly deform each one to give photo-realism?

Here's the latest version of the image I'm practicing on and the .Blend file. Thanks to a few of you who have already helped me get where I am! Thanks in advance to anyone who knows how I can tackle the next steps.

If anything I've done so far is a "rookie" way to do it and there's a better way, I am open and eager to learning the better way and changing my composition (or even starting over for practice)

My practice .Blend File

Answer 1

A few side comments.

1. You don't need very high subdivisions for such a simple shape.
2. You don't need to apply the subdivision
3. You don't need to Transform > To Sphere, you can use a Cast modifier.

To address you main question, if you want to add subtle variations to your objects your answer lies in a Displace modifier.

Now if you just add one to your M&Ms and duplicate them they will all have the same deformation and remain identical.

The trick here is to change the Texture Coordinates for your displace texture to Global so the texture is mapped using scenes world coordinate space, giving the impression of randomness across several objects.

Have in mind that this method is unsuited if you want to animate the objects, since the shape would wiggle around as you move them. You also cannot link as group/collection libraries since the coordinate considered for displacement is always read from the same static point in space the original was defined, not where each individual instance is placed at.

Answer 2

You can add Displacement Modifier to them with Cloud texture.

1. First add Displacement Modifier to one of them.
2. Click New, set Strength, Direction and Texture Coordinates values as in screenshot below (you can set different Strength). This will make each of M&M's different.
3. Go to Texture tab, choose Displace texture, switch Type to Clouds.
4. Set it as you like (you can change it later).
5. Select all M&M's and Right Click on the one with Modifier to make it Active (yellowish outline) than CTRL+L > Modifiers. This will copy Displacement Modifier to all of them.
6. You can tweak your texture as you like.

Answer 3

A Lattice

One suggestion (among many) would be a lattice. Here is a simple 3 x 3 x 3 encompassing my smartie, and applied via a lattice modifier.

Deform the mesh by editing the lattice. I've added a couple of shape keys to the lattice.

Variations of the strength of the lattice modifier, and shapekey values, will give subtle changes to each.

Apply the Lattice Modifier as a Shape

Finally can Apply the lattice modifier as a shape (once or many times) and randomize by altering the value of the mesh shape keys.