Sandbag modelling

Support Modeling
1

Hey there guys, just after some tips to model or sculpt a wall of sandbags realistically (ie not looking like a bunch of pillows). Especially where there’s creases pinching at the tied off area, and how to model the tied off area itself. Polycount isn’t a massive issue, as this will be for 3d resin printing.

Also how would you go around making the wall itself to make sure the sandbags look realistic in the sense that they sag a little and also easily follow a certain shape (eg like the curved wall below?)

sandbag
sandbag1000×1228 273 KB

Thanks in advance.

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hi, first you need to make some cloth simulation, modelling this by hand would result unrealistic and tedious!!

first model the bag as the simple template it would had, add enough subdivisions and then duplicate that template and then select the boundary edges (only where the seams should go) and use bridge edge loops and then select that face loop created and delete as only faces option (the edges will be used as seams)

and then setup a simple cloth modifier and be sure you set the sewing option in shape menu and enable pressure with enough value as needed, and bake the cache to the necessary keyframes (maybe 1 or 3 seconds) and be sure you disable gravity so that you dont have to add a collision plane (but later you will need that for the final simulation

in this part you want it to look puffed up if simulated successfully, and then apply the cloth mod, and readd it again without sewing option but keep pressure on (though i am not sure if leaving that still on will keep the bag puffed up), now for the second process:

edit the bag model and cleanup all the seams you added (every one them must be merged) so that you have clean topology…

create a simple rope model, add a bezier curve and add with a curve deform mod and setup it for the rope (in the rope not the curve object), then go to the curve in edit mode and select one handle and parent it to a hook using ctrl+H to new hook, do that to every handle you added, then go to object mode select the hooks and move and keyframe them until you get a knot animation with the necessary length, then setup a collision modifier for that as well, and make sure the knot you created is above the surface of the bag (in this case the bag i would put it facing upwards and same for the knot) and below enough from the hole so that it can have the chance to pull it together, then bake the sim to try to see if its working properly, and if not then keep adjusting the knot position (more above or below, left or right depending in the orientation), increase friction settings for the bag and rope perhaps (so that the bag wont slide off the knot)…

then the third process is to apply the mod again and duplicate this bag created and readd another cloth modifiers (reaadd the mod first so you keep the mod in every bag copy) and stack/position them as you wish, add collision plane and bake simulation for all objects and keep adjusting if not working or untill desired result…

let me know if have any questions…

3

Thanks, any tips on modelling the knot at the end? It kind of has a rose flower look, so is there a trick to model that?

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for a realistic rope, seek for a rope creation tutorial in youtube for better explanation, basically you will need 3 circles radial arrayed, a screw, array, and then curve deform mod at last…