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I need help trying to figure out the best way to make a sandbag wall. I've tried a few methods, but it doesn't look that good. I could just try again, but before that, I want to know if anybody out there has some tips that I could try out. I would appreciate any!

I have no issues making the sandbag itself. I just want to know the best to stack them without it flattening everything and going into each other. How would you do this?

Here's how I want them to look like:

enter image description here enter image description here

THANK YOU in advance!

edit!

Here is what I've done so far: I created a big mesh I call the barrier to form the shape I want the sandbags to fall into. It was my collision/passive mesh.

I duplicated my sandbag more than 20x and made it to active. I let gravity do the work and this is how it turned out. enter image description here I liked it, but I it doesn't look like a bag sand, but a bag of styrofoam.

I combined all the sandbags into one mesh so I can easily edit the cloth physics panel to reflect all of them. Not sure if that was a good idea or not.... but oh well. I thought doing a weight paint in the middle would help retain the middle and then do the cloth physics.. well that didn't look good. Okay now I know pinning isn't the best choice. enter image description here

Basically I want the sandbags to stack onto each other and I really don't know how to make it work. I could definitely do this manually, but I was hoping to find out if there was an easier way to do this. Maybe if there's a manual way to go about this without it going through other objects that would be great too.

Thanks again!

PepperAddict
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3 Answers3

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Final result:

You can use Array modifiers along with simple Sculpt to achieve similar result. It's a bit more of manual work but it's pretty simple and rewarding at the end.

final

Mesh:

You will need something similar to mesh from the screenshot. The goal is to have brick-like array. Top part is duplicate of the bottom part, cut in a half and manually placed.

mesh

Modifiers:

Here you will need at least two Array modifiers (width and height) or three if you want to have some multiple rows.

One of them (width, in this case X axis) should have checked Merge to connect top part of the mesh.

array

Sculpt:

When you make the wall with desired size it's time to duplicate it to another layer. To have some backup.

After it, apply modifiers from top to bottom. It's good idea to go to Edit Mode, Select All and Remove Doubles just in case.

You can add Mulitresolution modifier (I've added it with Subdivision 1) but it can stay low poly.

Go to Sculpt Mode, turn off Symmetry Lock X, choose Grab Brush and start tweaking the mesh. Remember to change Brush size/strength once in a while to give it more detailed look.

You can do this with mouse, no need for tablet to do this.

sculpt

Blend file:

First layer contain mesh with Array modifiers, second one is the final mesh.

Community
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cgslav
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  • I'm having a ... "Why didn't I think of that" moment. Thank you! This way may be the best since I'd have a lot more control! – PepperAddict Dec 22 '17 at 00:02
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    @PepperAddict Most important thing is that you can make it low/medium poly and without heavy CPU use. – cgslav Dec 22 '17 at 00:06
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    Nice technique, +1 from me! Now I'm wondering if one could achieve this fully non destructively with modifiers alone, replacing the sculpting step with a displace modifier. – Duarte Farrajota Ramos Dec 22 '17 at 01:19
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    @DuarteFarrajotaRamos I've tried it at the beginning but since some of bags are "smudged" over the others, Displacement just don't look well compared to manual method. It's totally possible thou but most irritating thing is that sooner or later Displacement texture will produce gaps between bags. – cgslav Dec 22 '17 at 01:34
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    Check my answer bellow :). The trick lies in the type of coordinates used and the direction of deformation. It will obviously never achieve the level of quality you get with manual sculpting, but it can achieve a vaguely acceptable result – Duarte Farrajota Ramos Dec 22 '17 at 02:06
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This was heavily inspired by LukeD's answer, but veers more towards an optimization route, in detriment of realism.

enter image description here

It is totally non destructive, fully modifier based, and uses a single instanced mesh object, for memory efficiency and maximum modularity.

The mesh itself is a trivial block box, with a seam in the middle, using a three-way Mirror modifier for the symmetry. It can be easily replaced by any other custom made mesh, with fabric wrinkles, or more detailed surface, which can then be clone duplicated to build the wall shape as desired.

The majority of the work for the irregularities then lies solely on two Displace modifiers, one for a large scale deformation and one for a small scale deformation

The trick here is to use the option under Direction set to RGB to XYZ, so that instead of "pushing" the surface along normals the bags are actually deformed in space in a more involving manner.

Also the Texture Coordinates should be both set to Global instead of local, so the deformations are calculated in scene world space, instead of per object; avoiding a repeated object pattern effect, and creating both consistent deformations between bags and matching continuity without overlaps or gaps.

enter image description here

Duarte Farrajota Ramos
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    Pretty nice! I had similar results with Color Ramping textures and playing with Midlevel, it looked more "pumped" (this was a method to hide gaps) because of it. Thanks for the RGB to XYZ tip, it's super useful! – cgslav Dec 22 '17 at 02:29
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    Welcome. :) Hum, Didn't think of color ramping textures, nice one, I'll have to give it a try also. – Duarte Farrajota Ramos Dec 22 '17 at 02:33
  • Oh man thank you so much for this. I didn't think to use the displace modifier. Thank you thank you thank you. – PepperAddict Dec 22 '17 at 14:31
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I think soft bodies are the way to go with this. But I am terrible at them and just playing around for a couple minutes seems like it would work. Baking times might be crazy though with that many sand bags.

You would need to play with the settings more to get the right amount of stickiness, mass and bounciness.

enter image description here

enter image description here

icYou520
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    Hey, thank you so much for your suggestion. I'm going to give it a try right now and then let you know how it turns out. I'm not sure why your answer had a -1. This was really helpful. Thank you again! – PepperAddict Dec 21 '17 at 21:32
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    Its not the greatest answer I admit but I was hoping maybe it can get you started, then when someone who knows soft bodies better than me could post a more complete answer. Also you may way to put some collision walls to hold up the bags from falling over, then hide them from the render. – icYou520 Dec 21 '17 at 21:36
  • This one seems so easy, but for some reason, my computer can't handle soft body physics. Thank you again for your suggestion. That does look like it is exactly what I want. I'll try again tomorrow! – PepperAddict Dec 22 '17 at 00:36