Carving rock directly from exuded foam?

KaiserWilhelm Jun 4, 2011

  1. KaiserWilhelm

    KaiserWilhelm TrainBoard Member

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    Hey all,

    I have a bit of a flair for the dramatic when I model, and despite the small size of my 2x6' layout, I'm going to feature a few dramatic, wave-carved outcropings like these in order to 'frame' the port/beach scene:

    [​IMG]

    I have heard that people can do some rather impressive rock work using exuded foam alone, and I'd like to learn more. Does anyone know of any handy how-tos that I could use to gather a few ideas on how to proceed?

    Thanks!
     
  2. Smithsr

    Smithsr TrainBoard Member

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  3. NYW&B

    NYW&B Guest

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    I can't say that I'm able to offer the URLs of any particular instructional videos on the subject, but I would like to point out that the technique, or modeling approach, used to render different sorts of rock types can vary quite significantly.

    The videos cited by the previous poster outline a fairly good approach to modeling metamorphic rock, although I've always regarded the interior texture of extruded foam as a bit too coarse/granular to do the job nearly as well as plaster can do it.

    When extruded foam is used to represent sedimentary rock, on the other hand, the modeling technique changes completely, but the end results are quite realistic. While I won't immediately go into the method used, you can see in the image below how a shale-like cliff that's on my layout appears. It was created using the foam alone.

    [​IMG]

    What I'm attempting to point out is that I feel you need to be a bit more specific as to just what type of rock formation you want to represent using extruded foam, since the techniques to create different types varies accordingly.

    NYW&B
     
    Last edited by a moderator: Jun 5, 2011
  4. KaiserWilhelm

    KaiserWilhelm TrainBoard Member

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    Probably granite, NYW&B. So I guess what I'd be going for is something with fairly clean, blocky lines since when granite weathers it seems to shear off and leave flat(ish) faces.
     
  5. NYW&B

    NYW&B Guest

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    OK, KW...given the nature and type of the rock formation that you desire to model, I'm not so sure that simple, carved, foam would be a better choice for a truly realistic representation. Traditionally, what you seem to want has been done using plaster rock castings...which, of course, can be simply attached to a foam base, or under structure.

    I'd recommend you try breaking/cutting up and stacking some practice pieces of extruded foam insulation board to see if you can get an appearance that is pleasing and seems representative of the real thing to YOU, as that is what really matters most. Plaster rock castings are very easily made and appropriately colored using various washes, so you might give that a try, too.

    NYW&B
     
  6. JNXT 7707

    JNXT 7707 TrainBoard Member

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    Glad you posted that - I'm carving out river banks of pink 2" extruded foam and tried to replicate what you did with an electric knife. Wow! Looked pretty impressive even before applying any paint. Did you use acrylics?
     
  7. KaiserWilhelm

    KaiserWilhelm TrainBoard Member

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    Alright, so I conducted a little experiment tonight just to see what I could do without using and kind of plaster molds or anything. I took a stack of foam that I glued together, then carved it with a square-headed hot wire cutter, then painted it flat grey (that would be a base coat normally, but in this situation I just wanted to look at the basic shape of the rock without it being pink). Here's what I came up with:

    [​IMG]

    [​IMG]

    [​IMG]

    Now, obviously there are some issues. First of all, I can still see seams, althougn my guess is some spackle would clear that issue up pretty handily. Also, without weathering, it looks very fake -- like the stone you see around water slides at Disney World. Also, it is missing all the fotsam and jetsam that makes it look natural -- the rock debris strewn about; boulders, slumps, etc. But what do you think of the overall shape and relief? Especially when compared to something (generally) like this?:

    [​IMG]
     
  8. NYW&B

    NYW&B Guest

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    KW, if that appearance pleases you, then that's all that's really necessary.

    NYW&B
     
  9. coasterp

    coasterp TrainBoard Member

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    I think you captured the overall shape. Try throwing some weathering and vegetation on and see what it looks like. Post some pictures too.
     
  10. mikelhh

    mikelhh TrainBoard Member

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    I reckon you're going well. Looking forward to seeing more pics as you develop it.

    Mike
     
  11. Tbone

    Tbone Permanently dispatched

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    I think they look GREAT!!!As far as the seams, they sorta look like strata lines.As someone stated above throw on some vegetation and I think you got it.
     
  12. NYW&B

    NYW&B Guest

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    Yes, JNXT, the painting was done with acrylics. I used pieces of local shale (tiny bits of which were also used at the base of my cliff) to match my paint color to.

    NYW&B
     
  13. KaiserWilhelm

    KaiserWilhelm TrainBoard Member

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    Well, I decided to take another approach to the same problem tonight just to see if another method was more crowd-pleasing. Here is a second-rock experiment. Which do you prefer, or should I attempt to blend the two techniques somehow?

    [​IMG]

    [​IMG]

    [​IMG]

    I'm going to try one more method tomorrow that I thought up while doing this one.
     
    Last edited by a moderator: Jun 9, 2011
  14. JNXT 7707

    JNXT 7707 TrainBoard Member

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    I like that idea. I have a source of shale in a rock garden right outside my front door. This thread has been a great find - thanks!
     
  15. KaiserWilhelm

    KaiserWilhelm TrainBoard Member

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    Alright, I think I've finally gotten something pretty decent going here.

    I attempted to treat this carving like it was a single, large rock, fractured in several places. I used less roughing action than on the first model, but more than on the second... and I varied it across the face of the rock. Obviously, the paint is still a little wet, but I am only painting them so they aren't blue when I take photos.

    [​IMG]

    [​IMG]

    [​IMG]

    Clearly, I'm still going to need to use something to take out some of the very evident lines... but other than that, I think this technique is what I am going to use to represent granite.
     
  16. MC Fujiwara

    MC Fujiwara TrainBoard Member

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    I dig your rocks!
    With the washes, veggies and debris, they'll look very good.
    (Careful your rocks don't out shine the trains ;) )

    To get rid of the seems, just work in some lightweight spackle.
    Make sure to spread some spackle around the rest of the foam, too, as spackle takes paint a bit different than the foam, and then you'd be trading a seem line for a wider band of spackle line.

    After the spackle dries you can carve it like foam to touch up areas as well.

    Looking forward to your progress!
    Rock on!
     

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