Sculpting cement cracks?

ENODMI

Anyone know of a good approach/ technique to making cracks in cement? Ive tried alphas but it seems to get too noisy, and ive tried sculpting them but havent found a good approach yet. Im thinking that a combo of modeling major breaks and sculpting finer details is the way to go, but I thought I might try and get some insight on this first from you guys before i keep experimenting. Also, it's major breaks and cracks im looking at, surface dtail and small chipping isn't a problem. Thanks:)

Stromberg90

I am no sculpter myself, but i do have a tutorial for you by Sascha Henrichs.

Worth to take a look at

http://area.autodesk.com/tutorials/mudbox_techniques_for_props_2_stone

[HP]

Zbrush and Mallet brush are your friends for cracked concrete.

divi

i like the slash2 with somewhat low intensity because its really easy to establish height differences with it but also have somewhat random edges.

Tom Ellis

I was doing exactly this today! My results aren't worthy of showing you but I got a kinda technique going which seemed to be working out ok, should look good once I've refined it some more.

I was just cutting cracks in using any brush that 'scooped out' a decent line, even the standard brush worked, but clay brush kinda gave a little more organic look. I found to get a deep enough crack, I had to make the crack pretty wide, then to pull the edges together I used the pinch brush with a big enough size and falloff to pull the edges together, resulting in a deep but thin crack.

To finish it off, right on the edges of the cracks I pulled them up a tiny bit either side of the crack using the claytubes brush leaving it rough on the crack edge, and smoothing the other side back into the mesh.

System

ENODMI wrote: »

Ive tried alphas but it seems to get too noisy

If this is happening the size of your alphas could be too large (zbrush likes small alphas: 256x256px is a good size) and/or the geometry is too low res. You need a million poly's + for micro details to show up and look sharp, try modelling the large cracks by hand then finishing it off with a good alpha.

felipefrango

I haven't got much experience in it either, but one thing I found to be quite useful was to use alphas as a base and then sculpt extra detail. I usually make my own alphas too, either from pictures on the net or from my personal pictures folder, so I can choose where to place detail and make it less noisy overall. Then I use either the mallet/clay tubes brushes to refine the shapes and carve a little more into the piece so it loses that alpha stamp feel.

ENODMI

Right on, thanks for ideas guys, Ill work some up and post back here later for some crits:)

GCMP wrote: »

If this is happening the size of your alphas could be too large (zbrush likes small alphas: 256x256px is a good size) and/or the geometry is too low res. You need a million poly's + for micro details to show up and look sharp, try modelling the large cracks by hand then finishing it off with a good alpha.

I did not know this! Ive been upping the resolution for a fix and it wasn't doing anything, ha! Thanks

felipefrango

Well, small alphas are better for small decals, but I don't think you'll get noisy details with a big alpha texture if you mean to apply it to a bigger area, right? I'd say the noise would be artifacts from the texture reduction which wouldn't appear if you used it in a size proportional to the size of the alpha. In the same way if you apply a small alpha to a big area you'll notice it sortof blurs out and loses detail overall.

Vrav

One thing that helps is if you have some sort of planar flatten tool, to brush out some of the planes of the bigger chunks. Then you can go in and define their edges, and whatever is visible of the cross-section where they broke away, which will create more geometric interest.

Also, reference is always helpful.

ENODMI

Vrav - yup, lots of images around me, went out and took some photos too this evening. Im shooting for something similar to your image on the right when I finally tackle my cement project. Do you think it would be better to sculpt out all the large broken pieces from one piece, or model all the chunks separate from each other...kinda puzzle piecing them together?

rough test but i think im getting an idea, i could definitely push the crack edges more
[IMG]http://enodmi.com/posting/cement test 1.png[/IMG]

Vrav

I think you have the crack patterns pretty well down, but if you're going for something with more depth as in the thing on the right, wouldn't you want to move it down a bit at the major points of impact / collapse? That way you can have pieces jutting up or being sunken further down... it sounds like that is what you're planning to do next, anyway.

Personally, I'd just sculpt it all from one plane or rough basemesh... simpler to deal with. Is this for some sort of blended-at-the-edges setpiece or a decal or something? What sort of geometry is the concrete crater going to be baked onto, I wonder? I've done some scribbling upon seeing the thread, but would like to attempt fully sculpting some shattered concrete myself now - thanks. :P

Steve Schulze

If it's too fine to sculpt, why not just use an automated solution like the NVidia filter or Crazybump and then overlay it? for something that fine it's unlikely to be noticable that it doesn't have the directional detail that the sculpted map has.

SpeCter

If you want to make something like the right picture, there was a tutorial for doing that in 3dsmax, which was very easy to follow, you just have the different chunks then, but then you could sculpt them.
Unfortunately i can´t find it at the moment, but basicaly the chunks were produced proceduraly an then he used a sphere to control it, so that chunks near the sphere were more inluenced then the ones around it to create the sinkhole(?)

(If you want dirt inbetween the gaps you could just use a simple plane and sculpt it acordingly)

If i find the tutorial i will post it here.


Found it:
http://area.autodesk.com/tutorials/interactive_fracture_system_tutorial
(you don´t need to do the ghosttrails part for what i meant)

you could also use the script mentioned in here for creating the chunks depending what you like better:
http://area.autodesk.com/tutorials/quick_shatter_tutorial

Here is a rushed result of it:


But i realized , that this is no geometry to sculpt at all(it could work with creased edges and or sudividing without smoothing etc. but i´m not sure at all)

felipefrango

ENODMI wrote: »

Vrav - yup, lots of images around me, went out and took some photos too this evening. Im shooting for something similar to your image on the right when I finally tackle my cement project. Do you think it would be better to sculpt out all the large broken pieces from one piece, or model all the chunks separate from each other...kinda puzzle piecing them together?

rough test but i think im getting an idea, i could definitely push the crack edges more

That's awesome as a beginning, you should now use a fine tool like one the Slash brushes (I think it's #2) to deepen the cracks, then Clay Tubes or Mallet or any other brush that works similarly to widen some of the cracks, carve in some of the chunks, sculpt on top of the chunks to put them on different heights and overall just try to remove the texture noise which is still very visible.

Will Faucher

The best results I've had with cracks, is using an alpha. Not a cement/cracked concrete alpha though. I use a lightning alpha. Notice how the cracks are lightning-like in shape! Best of all, it's usually white on a black surface making it great for getting cracks without the noise of a concrete alpha.

Mortague

Zbrushes surface noise can produce some great effects as well. The various options used in conjunction with masks and the morph target can yield great results. There is a video on their site which goes over someone doing a stone. Some of the principles may apply. http://www.pixologic.com/zclassroom/homeroom/

ENODMI

Vrav - Im building a pedestal for a small robot I recently finished. It's going to be several intersecting sections of sidewalk broken up with a small group of flowers growing in the middle. I think im going to model out the broken up sidewalk by hand and sculpt it out in zbrush

Jackablade - Thanks for the idea, but I think im going to have to sculpt it out since it'll be viewed rather close

SpeCter - right on! thanks, i was looking for similar tuts earlier

felipefrango - Thks for the ideas, I also was thinking of masking out sections of the cracks, building up the geometry and planar brushing it off for more height variations

Prophecies - Nice! Just saved a few zigzag bolts from google, they look strikingly similar to the crack alphas Ive been working with, but with less editing to do:)

Mortague - Awesome, thks!

Now lets see if I can do something with all these great ideas...

ncompton13

a quick suggestion would be to paint them out as a texture and then use the nvidia plug in for photoshop and create a normal map. if in maya use the normal and in lambert and don't forget to change the bump to tangent space normals.

ENODMI

[IMG]http://enodmi.com/posting/cement test 3.png[/IMG]

[IMG]http://enodmi.com/posting/cement test 2.png[/IMG]

Will Faucher

Now THAT'S what I'm talking about! Which technique did you end up using?

pthomas1172

- Crazy Bump & FLICKER.com. Search "Rock Face" / "Rock Climbing" / or "MONUMENT VALLEY"
- Download GOOGLE EARTH or just go here. http://www.panoramio.com/map
- Pictures of Ice / glaciers are great also





Patrick Thomas
http://patrickthomas3d.blogspot.com/

Rhinokey

i generaly make my alphas inverted from those that pthomas attached, zbrush for me seems to pull out the white bits, while leaving the black untouched, so when i use alphas like that it baloons out my model, when i make my alphas invert of that (you can also invert it in zbrush in the alpha menu) to where the deep cracks are white, you can use zsub when you draw them, and it pushes the cracks into your mesh, and leaves the over all shape of the surface untouched.

felipefrango

Definitely, your alphas should be white where you want the detail to be, not the other way around. Soft borders also help, especially when it's something you'll use repeatedly side by side such as pores or scales or something like that.

Rhinokey

felipe, i find it better to not do the fade on the alpha itself and just use the radial fade slider in zbrush (unless i want some crazy fade pattern) putting it in the alpha can limit the alphas use in some instances.

felipefrango

Hm, that's interesting, never heard of that feature actually. :T Sounds like it delivers the same effect but in a nondestructive manner, which is obviously better. Thanks for sharing.

ENODMI

did some simple breaks in the blocks and it turned out fairly nice. Im still experimenting with alot of ideas, mixing them up, trying to find what I think i'm looking for. I should have something more specific to say later. Thanks again guys, Im learning a lot of new things with your help:)

[IMG]http://enodmi.com/posting/cement test4.png[/IMG]

Ivory

I know this artist, and his robot picked my flower! Great support from other artisans on your concrete...lots of good ideas. I certainly know and respect the hours you put in to these creations.

swytch

Looking good! One note about your scene: you should adjust your view (or model) so that the hand not holding the flower is in better view. It overlaps the knee joint and gets lost. Rendering as silhouette sometimes helps with this.