Slicing 3D Models

[artisan]

I opened this new thread to discuss the slicing of 3D models and was wondering what methods other Botters were using. By slicing a model into 2 or 3 inch slices, you could theoretically build the Eiffel Tower or Staue of Liberty with a Shopbot. This technique is being used more and more in the theming industry and is extremely effective. Artcam includes a 3rd party slicer and you can use Rhino to achieve the same results. What other techniques and software are you guys using,
The Pharoah's head was made 3 inches at a time. The model was created in Rhino...D
image{Pharoah}

[artisan]

I'll post images a bit later....D

[Brady Watson]

Darrell,
You can also slice 3D in TurboCAD 10.2+. I downloaded the demo and tried it...it is VERY slow. There are not many programs out there that let you slice 3D. From what I understand, the only programs out there at the moment are ArtCAM, Rhino, TC and AutoCAD. Some better than others, ArtCAM probably being the best out of all of them for what we are doing. Some only let you do 1 slice and then you have to keep doing it with a lot of calculations in between.

Rhino is a great asset to me, but there are a lot of limitations with file types and the available functions to manipulate them. IE- STL solid vs. NURBS functions.

-Brady

[artisan]

Brady, that's been pretty much my experience as well....which is why I opened this thread. I wanted to explore and get some other possible options from anyone else working in 3D. Here is a recent 6 ft Pharoah's head we did for a nightclub: image{Pharoah}
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[artisan]

Next is a sliced foam model for an Anubis statue....12 feet tall:image{Anubis}

[artisan]

In this pic you can see the foam model and possibly pick out the three inch slices and glue lines. Foam:
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[ron brown]

Darrell,

I have been using RHINO for years to create slices for either toolpaths or sometimes glue-ups and laminations. If one takes some time and thinks about what a CAD program can do, they can conserve time and materials.

CAD is probably the most cost effective tool one has in the shop if used properly. Or, even as I do, just partially. One can visualize, build virtually, define joinery and if they have a CNC machine even define toolpaths.

Ron

[artisan]

Ron I totally agree. The possibilities are endless and the software allows you to overcome the physical size limitations of the table. It has really allowed us to do some very large pieces on a 4x8 ft Bot....D

Here's that Anubis statue....unfinished. I'm struggling a bit wth the pics...please pardon:image{anubis}
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[artisan]

Finally here is a shot of two statues in the finishing stages. These were part of a theming package for a nightclub along with several friezes and signs that I have recently done. Everything was cut on the Shopbot....in 3 inch slices....D: image{Anubis}
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[stickman]

Darrell,

That is the neatest work I have ever seen.

What is the project?

Do you have pictures of assembly and cutting? What are you using for tooling?

I can slice and dice 3d images in AutoCAD. My question would be machining each layer. I have Millwizard, is that a simple enough program for that?

How much hand detail work do you have to do after?

I cut a 57 Chevy convertible (12" length) from pink insulation. To be honest, I was tickled pink!

I'd love to spend a week working with you in your shop. I can manhandle a broom efficently, LOL. Not that I would want to steal your trade secrets, or anything like that.

Thanks for the pictures, love you work.

[Brady Watson]

As always, Darrell...VERY high quality work!

Oh...forgot to add MillWizard to the list...You have to do one slice at a time and a little math, but it works.

How are you currently handling undercuts? Hand carving?

-Brady

[artisan]

Thanks for the compliments, you guys are very kind. My intent is help us all push the limits and contribute to this forum...which has helped me so many times.
Brady: We can eliminate some of the undercuts by being clever with the cut files....the rest we do by hand.
Jay: Thanks for the offer, the finish work is always the most intensive part. I use the Bot to "block out" 90-95% of the model and hand carve the rest. The final finsh is determined by location and the clients pocketbook. We can do anything from browncoating and paint, to epoxies and polyureas.

I hope to see some other folks work in this thread. As you can see.... the potential is pretty strong if we can expand the software side of the Shopbot....Thanx....D

[jay_p]

Amazing work Darrell!
I have ArtCam Pro and I looked around trying to figure out how to do slicing, and I can't seem to find a slicer. Any hints.

Jay

[ron brown]

One of the things that will have you for lunch is inconsistant material dimensions. One should be sure the material and indexing system is "spot on" or it can cause some real puzzling anomolies that don't look like "register problems".

Light weight foams can have problems if a really "structural" glues is used to build laminates and the part deflects or moves a little when hitting gluelines. Bonding the laminate sections, especially fragile ones can be a frustrating event also. It will benifit one who tries this work to so something in smaller scale before trying a large piece such as the excellent work Darrell has shown.

Also, thought should be given to how to slice the project to avoid those "undercuts" and optimize machine speed by proper selection of router bits. As an example, something might only need real detail in the face, where a small ball-end bit might be used while the body may be able to be carved with a 1" Round nose bit. This would speed carving of the object by a huge factor and still give the desired effect. Even better might be to just cut the detail by hand.

Ron

[andrewm]

I use 3D Studio Max and it has a slice function which would work perfectly for this application. I haven't tried using it with the Shopbot, but I used to use it on some very complex models as an animation transition when I was doing broadcast animation effects. The slice is applied as what Max calls a modifier. You select the model and then apply the effect. It gives you a plane that intersects the model. You can then choose which part to keep. The results is a perfectly sliced model. I never thought of using it to make huge sculptures with the Shopbot. The wheels in my head are spinning.

Darrell, what software are you using to create your tool paths from your sliced model?

[gbatten]

Darrell, great work! Very impressive.

Could you share some info about your finishing methods. I am most interested in how you "hard coated" the foam before painting. My reason for asking is that I have been asked to carve molds and plugs from pink construction foam for a local decorative concrete products manufacturer. They want to use pink "Foamular" foam, if possible, to save money over the expensive HDU foam. I can carve it fine, but I need to find a good "hard coat" material to coat it with after carving and before painting.

Thanks for any advice.

[Brady Watson]

Gene,
You can use either epoxy (I like MAS brand...cleans up with vinegar) or StyroSpray to hard coat FoamulaR. Either work very well, leaning more towards the StyroSpray now because it doesn't 'pimple' the foam like epoxy does.

-Brady

[halmande]

Darrell,

Wow, Wow, and quadruple Wow….your work is from heaven, man….I am impressed and I would need you help defiantly.

I have been suffering with my 3D slicing technique it is just over my head. I have designed some pieces of furniture that I would like to build out of plywood and slice and cut in 2D.

Could you please briefly explain what softwares to use, and I will get the softwares. Also, can you tell me how to slice a model . I am Using Artcam Pro 6.

Keep up the good work.

Regards,

Hani

[billp]

Darrell,
Great work.......! You're right, there are no longer many limits...
A couple of us are trying similar slices, mostly using the Artcam "Relief Slicer". ( For those who already have Artcam it is on your release CD in a folder called "unsupported programs" I believe). To use it you would need to create an Artcam relief file, then just follow the 2-3 steps and it will give you individual "slices"in any thickness you ask for.
As for undercuts my "fifth axis" is a hacksaw blade which carves Foamular cleanly, and fast.Then it's some 150 sandpaper, and either of the two coatings Brady mentioned earlier in this thread...
The tricky part around here is GETTING the 3"foam to carve. Currently I have to drive 70 miles to Hoboken as no one can tell me anywhere closer that handles 3"thick, 48"by 96"sheets of the stuff. Anyone have a lead?

[billp]

Just got a phone call from someone who wanted to see what the "slicing" process looked liked. I have a few quick pix here, maybe others can add theirs as well.
These slices were done with the Artcam relief slicer. I had a 21" model which I needed to build with 3"thick slices of foam. I gave those two facts to the relief Slicer and it gave me 7 separate files for slices.
The first shot shows the two larger slices being cut.
The second shot are the slices being stacked and glued up.
The last shot shows the piece almost totally assembled, and coated with 3 coats of Styrospray ( brushed on as it dries fast...)
There is now also a "panelling" feature in Artcam 7 which lets you draw a file larger than your table, and it will break the files down horizontally and vertically so you can now scale all 3 dimensions of a project and as long as you have enough foam, build just about anything you'd like...Hope I can post these images all at once. if not I'll do them separately
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[billp]

Second try..
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[billp]

Last one..
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[artisan]

Bill has answered the question of the Artcam slicer....it's on the disk and is a 3rd party piece of software. I also use Rhino and recently 3DS Max to manipulate models. The beard on the Pharoah for instance, was sliced off in the software and cut separately to avoid the undercut. It was then simply glued on and finished in place.
Bill.....check with your local STUCCO guys. They'll point you in the direction of the local foam supplier. I usually split a truckload with a friend of mine and just order it in 3 inch sheets already cut. If you store foam outdoors, be sure and cover it....sunlight breaks it down.

As for finishes.....I could write a book. I have a plural component system that is capable of spraying a hardcoat on the foam....but I only use this method about half the time. Styrospray can be sprayed with a regular hopper gun (spray the inside of your hopper with furniture wax first) or it can be brushed on and is available from Industrial Polymers. I use epoxies in various forms, depending on the application and have found this to be the best when preserving detail. I use what stucco guys call "browncoat" very often. This gives a hard but "elastomeric" finish to the foam. It can be sprayed on repeatedly, and can be carved, sanded and detailed. There are other coatings like Vanillacryl which are water based and do a nice job where constant handling is not a problem. Use Enerfoam spray glue system to glue up your pieces.
Thanks for the comments. I look forward to more new ideas....D

[mikejohn]

In AutoCad, slicing is quick and easy.
This took about 5 minutes, including creating the solid shape.
Note you can have slices of any thickness, see the cyan slice half way up the model.
From these slices, you can make 2D or 3D toolpaths.

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..Mike

[artisan]

Thanks Mike....that's EXACTLY the kind of info I'm looking for. I know there are Many more ways to skin this cat. I'm always looking for more control through the software and I like the option of being able to vary the thickness of my slices. This will help with mold making and undercuts. Time to dust off my copy of Autocad and take a look at it. I'm using Visualmill for most of my toolpathing...D

[mikejohn]

Darrell
What I particularly like is the ability to slice in any direction (up-down/Front - back, left-right).You could even slice in segments, like an orange, if you wished (though for what purpose I can't think). You can also slice at an angle, if it saved undercuts.
Also, every slice can be a dfferent thickness, if it helped construction.
What I also like is the ability to place alignment holes through the model whilst it is still solid.


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Believe it or not, I do this on a pin router with jigs at the moment
Roll on my ShopBot

....Mike

[halmande]

Mike,

Thanks for the information. Could you please provide me with brief steps of how you can you achieve the slicing in Autocad.

Hani

[billp]

Darrell,
When you use the hopper gun for Styrospray are you getting any "runs" as it sags on vertical surfaces? I wound up having to do small sections by brush, and really brushing out the foam, but it still wanted to sag on me... I'm thinking the spray techniques might lay down a thinner coat, but this stuff was kicking off on me after about 20 minutes , even in small quantities.
I have used good old rubber gloves, and handfuls of FSC-88 (water based) to just "rub" a surface coating into styrofoam as well. It gets into the "pores" that way, and really stiffens up the surface enough to apply something else as a finish coat. That's also how I handle the transitions from one slice to the next..
P.S. Simon, yes, some of the threads on the Forum run "backwards"and you have to check the times to see which direction they are running..

[mikejohn]

Making slices in AutoCad
There are a number of methods to do this.
I will use a cone to illustrate.
Method 1 is for 2D cutting.
Ensure your model is orientated with top to the top, front to the front.
Select FRONT view
Select ORTHO and OSNAP on.
Draw a line from the base to the left (or right) so the end is outside of the model.
OFFSET or ARRAY the line the spacing of the thickness of the material you intend to cut.

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Command section
Select model
ENTER
type ZX ENTER
select the end of the first line you drew earlier.
Repeat
Select model
ENTER
type ZX ENTER
for the remaining lines.
Delete the model and lines you drew earlier.
Select top view, you have the contour lines of your model.
Move each contour by selecting the line, move to 0,0,0.
Move this out of the way,select the next contour line and MOVE to 0,0,0
Continue for all contour lines.
Now arrange the shapes for best nesting, and cut.

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This took me under 5 minutes to do, for 10 slices. Obviously more slices would take relatively more time, and nesting complicated parts would take some time.
You end up with a model that needs some finishing, so we need to look next at preparing slices for 3D cutting.
Others can say whether software apart from AutoCad can do this.
3D will follow.
....Mike

[mikejohn]

Making slices in AutoCad
This is another method to do this.
I will again use a cone to illustrate.
Method 2 is for 3D cutting.
Ensure your model is orientated with top to the top, front to the front.
Select TOP view
Draw a BOX A little larger than the model, with a height the thickness of the material you wish to cut.
Select FRONT view
OFFSET or ARRAY the box the thickness of the material you intend to cut.
COPY the model and boxes and position beside the original.
Command subtract
Select the left 3D model ENTER
Select the base box on the left hand model, and then every alternative box, going up.
ENTER
Now do the same for the right model, starting at the box one above the base.
Delete the remaining boxes.
You now have a series of 3D slices
Now arrange the shapes for best nesting, and cut.
This took me 5 minutes to do , for 10 slices. Obviously more slices would take relatively more time, and nesting complicated parts would take some time.
You now have the pieces for a 3D model.
In real life, I would have put alignment holes through the model before slicing.
As before, others can say whether software apart from AutoCad can do this.
For some reason, I can't upload the sketches this time

....Mike

[mikejohn]

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[mikejohn]

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[normand]

Thank Mike now you have some well deserve rest

[halmande]

Thanks Mike,

I'll start testing and slicing modles.

Hani

[halmande]

How do you slice models with Rhino?...

Help needed...

Hani

[ron brown]

Rhino is more of a surface modler than a solids modler - IMO. Cuts made in Rhino will not have surfaces on the face and these must be added if needed.

Build object; define cutting plane - I normally will use the surface/corner points command and copy those into position; use curve/from object/intersection or the split command - maybe a combination depending on what you want. Other useful commands that might be of use for defining sections are "project line to object" and "trim".

Be sure and make lots of backups and use lots of layers. I've only been using Rhino for a few years so I don't know all the commands.

Eon

[halmande]

Ron,
Thanks for the information. Do you know of any good software to slice models?

Hani

[hhowlett (Unregistered Guest)]

This is a great thread. I was interested in the exact types of foam boards that are used and where to get them. I have not machined foam before.

[ron brown]

To whoever is responcible for having all threads go in one logical direction, Thanks.

Ron

[mike_annetts]

Hello

Does anybody know if slicing is posible in Mastercam?
thanks
Mike

[Jack Smith (Unregistered Guest)]

Here's another option for a coating for foam projects.

http://www.fxsupply.com/vanillacryl/vanillacryl.html

[treppeka]

Question for my Masters, lol
Many suggestions have been given in this thred, but unfortunately I havnt found any information specfic for my intended applications. May I have a suggestion as to what software to use to Design,slice,and set tool paths to make a scaled human head. i.e. ( head with facial detail )

[billp]

I use Artcam, and it's supplementary program "The relief slicer". Simple, accurate, and fast...I think the REAL problem here is actually generating a 3D model of a human face, particularly with hair. Hair is the benchmark that separates many programs.
Poser does a fair job as it has many "plug-ins", but in most other programs you have to DRAW the details of any hair, or facial hair.

[Brady Watson]

Jason,
You can do it in Rhino as well, although it takes a bit of planning and is not as elegant as ArtCAM. By simply creating a flat plane and using it as a guide, you can delete the mesh points up to that line and export it as an STL.

Here's an example that was done in Poser5 and brought into Rhino:


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-Brady

[gerald_d]

Was strolling around a touristy area here in Cape Town a month ago and found a guy putting 3D portraits into crystal (http://www.inspeck.com/products/crystal/crystal.asp). He sits you down in front of a "3D camera" for a couple of seconds, then you come back an hour later and collect your chunk of crytal (about fist-sized) with your 3D portrait inside, all for $50. Started to chat and he tells me that does an stl file from the camera. Agreed that one day we can see if we can use his stl for SB type stuff, but havn't gotten around to it yet. All of this to say that there might be someone near you with a "3D camera"....

[mikejohn]

Jason
Although this isn't exactly what you want, I am working on something very similar as we speak.

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Its the body of the rockinghorse, which is made of 20mm (4/5") slices
The problem I am finding is not the outer shape, but getting the angled mortise for the leg tenons, and then where to place the screw holes. A screw is countersunk into one piece, goes through a hole in the next piece down, then screws into the third piece. Everything is glued, but the screws hold the pieces together whilst the glue dries, and are also good insurance. In the years we been following this method (although not CNC cut) we have had absolutely 100% no cracking.
There are 11 boards, the middle 6 are made from two pieces, cut 1/3 from alternative sides, joined with a keyhole piece, giving us the strength of two glued cross grain parts per slice.
I had to abandon one method of drawing as it became impossible to track all the different operations through the parts.
This new method 'makes' each individual slice, with the division of the middle slices and keyholes next, then the placing of the screws.
As this is in Autocad, taking the pieces slice by slice and making the tool path is very straightforward.
I would suggest that you think the whole thing through from the start to arrive at a technique that is as straight forward as possible.
Rocking horses take a hundred years of pounding and strain, plus they have to stand up to central heating problems, so our slices can not move.
I guess if you are using man made materials, and are only interested in creating the outside shape, it may be simpler.
...............Mike

[mikejohn]

This is a slice awaiting for the outlines to be offset 3mm (6mm bit) to make the tool path.
The two parts are have a 10mm separation, the lower on zero, then one at +10mm, for two passes at 10mm depth. The countersink holes are set 5mm above the 10mm level.
From this toolpathing is simple
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[billp]

Gerald,
I have one of the Inspeck 3D cameras here in my shop "on loan" from a friend. We have done a LOT of experimenting with it, and found that while it gives a very clean image in the "crystal mode", it still needs some software "sculpting" to make a marketable item. The newer software (180 degree option) MAY eliminate some of the "stiching" we have had to do in the past, but since we have found that a slightly turned head makes a more interesting bust, it may not work as well either.
We have taken the SAME image and run it through their crystal software, and 3D software (both are supplied with the camera), and the crystal images are by far the better of the two.
Ballpark pricing, 15 grand depending on which size lens /camera you purchase. If I ever get the time I want to try it as a simple 3D "scanner" but time is an elusive commodity these days. The main benefit of the Inspeck unit is that it does a fair job of capturing hair, which otherwise means considerable modelling time. I'll attach a picture of something I generated after using the unit...
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[gerald_d]

That's all very interesting Bill! This one guy that I met (apparently there are a few more here) doesn't use a camera that looks like those Inspecks, but I am sure that results would be similar across different brands. This guy will do a "photo" plus stl file for under $50 so we didn't even ask the price of buying our own camera.

Did you make the left-side guy for the photo and then make the right-side, or did you make both?

[mikejohn]

This company www.photomodeler.com (http://www.photomodeler.com) sell software for under £500 that enables you to produce full 3d .dxf files using you normal camera. The quality of the final model depends on the number of photographs you use and the time you spend on creating the model. You can also select the most appropriate portion of different photographs to give a fully photographic rendered 3D image.
You can import into AutoCad and Rhino amongst other programs.
If you want to make a model of Mount Rushmore or the Sphinx (or all of Gerald) then this is probably the only way to go.
You can download a demo version of the software.
You still have to slice your 3D model though.
............Mike

[billp]

Gerald,
I did both busts, each are at a slightly different angle from "head on". We were trying to see which angle would be the best to add detail, without having to take too many pictures. If that guy will do the 3D photo, AND the .STL file I would think it's the smart way to go. Good "stitching" software is pricey, and time consuming.
Mike,
I believe I tried an earlier version of PhotoModeler and found that their sales people were apparently over enthusiastic about the realities of creating 3D files from photos. I think it still involved using "primitive" shapes which would then be applied to "fit" the photo to the geometry needed. NOT easy, or intuitive..."and the time you spend on creating the model" can mean
a LOT of time...

[treppeka]

I dont have the big bucks for ArtCam Pro. Does the Educational version still have the relief slicer you mentioned? I already bought MillWizard, but havnt got it yet in the mail. Does anyone know if i can do 3D slices with it? Thanks again for all your advice everyone.

[treppeka]

Dumb question sorry, saw up top about millwizard doing one slice at a time

[mikejohn]

Bill
The latest PhotoModeler has progressed since the early days. I'm not sure about not easy or intuitive, but as it uses the same mathematical models, and similar techniques, as they do making maps from Aerial Photos (my previous life ) I my have a head start
.
I do agree it takes a lot of time. More time + more photos = more accuracy.
If you can put it on the table, probe or laser scan it. If it's alive, Gerald and Bills idea sounds good. Mount Rushmore? Photo Modeler, or similar, would be the only way to get it accurate.
I guess its a trade off of time against cash outlay.
............Mike

[Brady Watson]

Jason,
My post from November insinuates that you can slice with illWizard....What I meant to say was you could slice in Rhino and Toolpath the slices in MW.

-Brady

[btk]

Does anyone know of a source for a 3" cutting length ball end mill(i.e to cut 3" thick foam).

Edited: looking for 1/8" or 1/4" diameter.

My local supplier is no longer carrying.

Thanks.
Brian

[billp]

Try MSC (www.mscdirect.com (http://www.mscdirect.com)), That's where I get my longer bits from.

[btk]

Thanks, I will give them a shot.

Brian

[gerald_d]

For cutting soft, brittle foam I've had acceptable results from a normal HSS twist drill.

[btk]

Gerald,

Good Idea, I will try that as well.

Thanks,
Brian

[ron brown]

Tapered end mills work well too if one is just needing the accurate point. I have used conical tool company's bits with good results.

Ron