seeking classes to fill in the gaps - materials, 3d printing

I've been watching classes to learn how to make an animal puppet character.  This is a garage production.  It will likely be a hand puppet as far as the mouth and head movement, but I do want some expressiveness in the eyes and brows so I'll do mechs for eye movement, eye lids, brows, etc.  Organic Mechanics has been really great and there are a ton of great ideas in there.  But I do plan to build mine in 3d and print parts with a large format resin 3d printer.  So my plan is to print the mech parts and reinforce as necessary with metal parts.  Also to print the core/inner skull that will attach to (or be) the mech, and print a mold for the skin - so that the skin can be injection molded.  Then apply fur on the skin after assembly.  But as I learn more I'm adjusting my plan.

I've seen the class on 3d printing an eye mech and it was also extremely helpful.  And my 3d printer is much better and much more detailed than a traditional FDM.  And there are a variety of resins/materials for different strength and tension properties.  I know that all of this will require a LOT of experimentation, testing, retooling, etc.  I think I can handle the design portion.  But I'm looking for assistance with understanding materials.

More than looking for these answers directly, I'm looking for classes that will help on this journey.  Maybe someone can suggest something.  These are some of the questions I'm looking for answers to:

1. I'm unclear on what materials stick to what.  I see in organic mechanics that Rick had a clay mold to make the skin which I believe is foam rubber.  Why did it have to be a baked clay mold?  I've seen that people have 3d printed molds but I'm curious if that will really work or why it wouldn't.  I'd love to print the negative directly as opposed to printing a posive and then making a mold from that.  So I guess my question here is just about where can I get info to understand the different materials and how they interact.  When to use release, etc.  Assuming that I'm 3d printing everything I can, not clay sculpting anything.  How to get from A to Z in the least number of steps.

2. What are my options for materials for the skin and what's the advantage of each? There's probably a course on this but with only getting 4 courses a month I'd like to hit the right one the first time.  I'm still undecided about fur.  I'd rather avoid a muppety looking character and instead would like something more in the range of a fantastic mr fox in terms of realism vs stylized.  So when I get farther down the road I'll need to decide on a skin material probably based on whether or not I'm punching fur, flocking, or using a more traditional solution for hand puppets - a fur material sewn to form the "skin".

So for the material, it's assuming I'd be injection modling it, hopefully using a resin mold that I printed, that can take punched fur and possibly flocked fur, and is flexible enough to have those brow movements and other expression mechanics in it.

There are some flexible materials for 3d printing but I think those are still too stiff to use for skin.

3. Fur... I found the class on flocking and punching fur.  Hoping that it includes some info on where to source those materials.  I'm sure it will.

-Michael




Comments

  • Chris EllerbyChris Ellerby Los Angeles Admin
    Hi Michael!

    Lot to answer here, so I'll do my best to cover it all.  If I miss anything, just let me know and I'm happy to help!

    FDM and SLA printers both have pros and cons in different applications.  Both are regularly used by effects studios large and small, as well as SLS.

    For question block 1:   

    A good resource for finding out what adhesives to use on different materials is http://www.thistothat.com/ . Otherwise, if you have specific examples I can provide more info.'

    Your question about baking and "baked clay" is a little confusing.  He was using foam latex (which is baked) typically in stone (ultracal 30, hydrocal, etc) molds, and sometimes fiberglass molds.

    As far as baking in 3d printed molds, that could work for some SLA or possibly SLS molds, but that is not really ideal from a cost or durability perspective.  If your goal is to use 3D printing you may want to print your form, then mold that using fiberglass etc.  If you have specific examples, I can help more.


    For question block 2:

    There are lots of skin options, each with pros and cons.  Foam rubber is light and flexible, but can break down over time.  Silicone can be more durable, but is much heaver and harder to move in some situations.

    If you are interested in fur, I would also suggest our lesson on fur transfer, flocking, and punching:  https://www.stanwinstonschool.com/tutorials/fur-transfer-electrostatic-flocking-and-hair-punching

    Form Labs has a new SLA printing material that is quite flexible, but it's still not as soft as what you would want for a character's skin.

    /Chris


  • edited May 7
    Thanks for those answers.  We're on the right track. :smiley:

    On the baking of foam latex.  That does answer why he had what I thought was a clay mold.  He went over the mold process fast as it wasn't what the course was about.  So I assumed that when he said it had to go in the oven he was talking about making the mold, not what he was casting in the mold.  Looking at that lesson again I see he says "ultracal mold", which is like a plaster.  I wasn't aware that the process of casting foam latex required baking.  So that answers that.  And it's not really a good solution for a garage production because I don't have an extra oven laying around.

    So back to the question of materials.  Is there a direct castable (no baking required) option for the skin of a puppet (like the cougar in organic mechanics) that I can punch fur into?  And that will be durable?  And is there a swsca course on casting or mold making that would answer this question?  Perhaps the fur class you mentioned will.  I would like something more durable because I don't really want to have to make too many copies of the puppet.  I'm not skilled enough to match the finishing exactly.

    Then the next question for me (which will require experimentation) will be can I print the mold directly with my LCD resin printer, rather than having to print a positive, then create a mold of that.  I have a Phrozen Transform on order but it won't be here until August.  And I'll check out thistothat.com on the question of materials sticking to the resin.  Thanks.
  • Chris EllerbyChris Ellerby Los Angeles Admin
    The baking temperatures for foam latex are pretty low, so most people make their own foam oven using a heating element in an insulated box with a fan to circulate the air.

    For a skin that does not require baking, you can do silicone.  There are also 2 part foams that are quite flexible (polyfoam) that can be used as skins as well, depending on how the character needs to move.  Silicone is the most durable skin.  Only down side is it can be a bit heavy depending on the thickness and size of the character.

    This lesson shows casting up a silicone puppet character in a fiberglass mold:  https://www.stanwinstonschool.com/blog/make-a-rod-puppet-monster

    That character is not a skin, but a solid casting, but some of the ideas are the same.

    On our main lessons page (https://www.stanwinstonschool.com/tutorials) you can also filter by category ( like Mold making ) to browse around too, and see if anything feels like it would fit your goals.

    You can print molds for silicone casting as long as your printer can do the size you are after. 

  • Thanks for all your help!  More good info.

    The 3d printer I bought has a large print size: (11.5 x 6.5 x 15.75 inch) and the prints look amazing. Very high detail. Its a kickstarter so I have to wait a few months before it will arrive.  But we're getting close and it should be here Aug or Sept at the latest. But the company has a really good track record and there is good community support for it.  In the mean time I'm trying to learn as much as I can and then I will start on the design process.  I'll hire out the Zbrush sculpting if I go that way, as that's not my strength. But then I'll do the 3d modeling for all the mechanical parts and I'll do the physical build out.

    https://www.kickstarter.com/projects/phrozenmake/phrozen-transform-the-lcd-3d-printer-that-lets-you/description

    I already watchted the make a rod puppet class which had some good info in it.  I'll check out the tutorials page.

    How it needs to move... I'm still contemplating the design part and where I want it to land on the spectrum with full realistic on one end and ping pong ball eyes muppet on the other. There are so many options.  And if it's more puppety there isn't a sculpt or a skin.  Just some core mechanism and cloth or fur.  But I think I'm leaning a little bit realistic with fur punched in a skin and some expressive movements.  But still styalized and not completely realistic.  For sure these classes make me feel like it's all possible.
  • Chris EllerbyChris Ellerby Los Angeles Admin
    That printer does look quite interesting.  I'm excited to see more SLA printers on the market, as that competition will really improve the technologies while reducing costs.
  • FYI my printer is technically not SLA.  It's LCD.  SLA uses a laser to draw the image on the slice.  The more surface area the slice has, the longer that slice will take to expose.  DLP and LCD printers use an imager to expose the entire slice at once. DLP uses a reflective imager like a DLP home video projector, to project the slice on all at once.  LCD uses an LED panel and an lcd panel (like on a tablet) to prevent the light from getting through to expose the slice.  These technologies therefore print faster than SLA.

    The tradeoffs have to do with some of the qualities of the print, and some cost in expendables.  SLA can have extremely smooth edges as the laser moves in a line from point to point, similar to how the vector screen in asteroids produced super sharp edges back in the late 70's.  Compare that to LCD and DLP which have pixels on their screens which essentially create voxels in the 3d print.  This means a possible stair stepping on those edges.  But those can be mitigated by using anti-aliasing.  Even still the resolution of these printers is much much higher than that of an FDM.  Instead of a 3mm nozzle (3000µm) you have a pixel size of just 76µm or 47µm.  So 50x the resolution of FDM.  Therefore even with the stairstepping it's so small that it's difficult to see.  And by tilting the object on the base at a 45 degree angle you can reduce the appearance of stairstepping even more.

    Then you also have the limitations on size, because for example the total slice area is limited to the size of the LCD panel.  But with current LCD panels that has now been raised to a 13" panel (diagonal) in the Phrozen Transform.  Giving us an 11.5 x 6.5 slice area.  So in my opinion that is large enough for my uses.

    Finally the other downside to LCD is that the liquid crystal panel is degraded and damaged by exposure to UV light. So it becomes an expendable item.  At under $100 for a replacement panel it's something that can be calculated in to the cost of printing.
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