3D modelling and 3D printing - frustrated!

Up to now I have used OpenScad to create models for 3D printing and I am very happy with it. However those models have all been of a technical nature - with holes in precise places and precise dimensions etc.

I am now thinking of making some models that are "artiistic" rather than technical - in other words shape is more important than detailed dimensional precision.

Two 3D modelling programs that seem to be reasonably easy to learn are Wings3D and Art of Illusion - they are quite similar and easier to learn than Blender because they have less features.

What is frustrating me is that I can't find anywhere the information about how you specify the size of a model - in other words what size it will be when I 3D print it or carve it with my little CNC mill. None of the tutorials that I have found goes right through the process from design to the finished 3D print.

I'm wondering if any of the Forum members knows how to set the size of models?

...R

I think I have found a solution - that was staring me in the face all the time.

I have a program called DeskProto for creating Gcode for CNC milling and it has an option to set the X, Y and Z dimensions of the object that is contained in the STL file. Of course this still means that the proportions in the design have to set by eye rather than measurement as the object is being created.

Previously I have (as mentioned) been using OpenScad to produce dimensioned objects and using Slic3r to create the GCode for 3D printing. Slic3r has an option to scale the object by % but I have never needed to use that. And Slic3r does not seem to have the option to set dimensions. Consequently it had not occurred to me to use the sizing capabilities of DeskProto.

DeskProto could be described as the CNC milling equivalent of Slic3r, although it is intended for quick prototyping rather than high precision milling. It is a commercial program that can be used for free for evaluation - and I think it may be worth the fee. The path generation feature in FreeCAD seems to be a reasonably straightforward way to create precision Gcode for milling from an STL file - but the extra precision means it is more complex to use then DeskProto

DeskProto can also use an image file and convert the grayscale into cutting depths to make lithophanes.

...R

Not familiar with the software you mention but when I prep for 3d printing I use CURA as it lets you scale directly even if you over / under specified the original sizes.

I always liked sketchup until they made it web only as that was simple enough to get your head around.
Running an older version here to stay on the desktop version but they killed some online links for the 3d warehouse.

For Lithos I still use CURA as it will accept a good few pictures and directly convert.
Although I tend to do an prep work in Micrografx, which is very old but still works under win 10 down to XP.
You probably need to wander the linux graphics forums for your specific needs.

IIRC CURA also runs on Linux.

ballscrewbob:
Not familiar with the software you mention but when I prep for 3d printing I use CURA as it lets you scale directly even if you over / under specified the original sizes.

Thanks Bob,

Can you specify the X, Y and Z sizes in mm in Cura (rather than a percentage of the original).

I seem to recall that you created some elaborate cnc milled artefacts - did you use Cura to produce the GCode for them?

...R

Yes you can specify x,y,z or unlock and perform some extrusion techniques.
Some size distortions may be noticed in the extrusion modes but so far I have found them manageable as I am not getting crazy with them.

EG. laying an object FLAT on the bed and extruding in the Z axis is great for some added depth to features.
Or turning a ring into a tube.

Like my coding skills it is more a hack and slash approach with bits from here and there using YEGGI or THINGIVERSE as a basis for something else...Consider it a LEGO approach LOL.

Presently playing with LITHO's from client supplied pictures on the 3d printer which has been given a resounding welcome by those involved.

Actuall CNC is awaiting some new motor brushes before In start my xmas run up into new materials for nest years shows (hopefully).

CURA starts you off in basic mode but you can go real crazy with settings if you want.
DON'T try use CURA g-code on a CNC as it works from the bottom up NOT top down like regular g-code does.

It also lets you save the projects in a wide variety of formats allowing you to import and export most common 3d and draughting formats.

BLENDER may also be worth a little of your time for manipulation but it has a slightly steeper learning curve.

ballscrewbob:
DON'T try use CURA g-code on a CNC as it works from the bottom up NOT top down like regular g-code does.

That's what I thought - same as Slic3r.

BLENDER may also be worth a little of your time for manipulation but it has a slightly steeper learning curve.

Wings3D and Art of Illusion are (for me) much easier to learn than Blender and have all the features I'm likely to use.

Another thing that I might try is creating a JPG image in shades of grey where the shade represents the depth and using the feature in Deskproto to create Gcode for a Lithophane. Normally it makes the deepest cut for the lightest areas so that more light can pass through. For engraving a block of wood that would result in a hollow model. I assume I can trick it by inverting the shades.

...R

Am finding that once I have the file in STL, OBJ or similar formats the rest is quite easy for the g-code generation in either top down or bottom up.

CURA / SLICER for bottom up.

I use an older version of artcam (now defunct) for top down but I would imagine there is something similar in Linux

Inkscape or GIMP also both available for Linux have a multitude of offerings for code generation too.

ballscrewbob:
Inkscape or GIMP also both available for Linux have a multitude of offerings for code generation too.

I have both. I really only use Inkscape because it has an add-on that can drive my Silhouette Portrait CNC cutter. For my vector drawing I use Libre Office Draw as it has more standard shapes than Inkscape.

I suggest you have a look at Deskproto.

...R

I had waaay too many cad / cam programs on my old computer.

Sort of settled into a few that I like for ease of use and functionality.
It allows me the best of both worlds and a few good crossover points in between.

Most of my stuff starts out as a regular picture anyway and goes from there.
Very little from concept (except in my head)

My laser work is just varied degrees of BURNT :grinning:
Other stuff is just graphic clean ups, overlays, and quick conversions to STL, OBJ files.

I am a very lazy g-coder and only occasionally tweak some of the settings.

ballscrewbob:
I am a very lazy g-coder and only occasionally tweak some of the settings.

Me too

...R

One of my hobbies is 3D printing too and I spend a lot of time on it.I also want to create my own YouTube channel about 3D printing. But for the last six months, I've been putting it off because there were a lot of problems besides. But maybe in the new year, I will do it. I still want to buy a new 3D printer, a more professional one, and a good camera to shoot video. It certainly takes a lot of money, but I hope I’ll find them. So maybe someday I will become a famous blogger)

I LOVE 3D printing.

@robin2 Possibly you could take the path used many times in the "real world". Make a framework, or fixture with the important dimensions for your artistic 3D stuff in openScad. Then import that into you more artistic software?

-jim lee

jimLee:
Possibly you could take the path used many times in the "real world". Make a framework, or fixture with the important dimensions for your artistic 3D stuff in openScad. Then import that into you more artistic software?

Thanks. That's an interesting idea.

I confess I have not been focused on CNC milliing for a while now - I tend to get blips of enthusiasm and then they fizzle out for a time.

...R

I don't know if your fizzle is due to Covid or not. But I find that myself and ALL my creative friends currently have the EXACT same issue! Its like being separated or something is just killing our enthusiasm.

I hate it!

-jim lee

jimLee:
I don't know if your fizzle is due to Covid or not.

In this case I don't think so. I tend to flit from one enthusiasm to another even without Covid.

But all these Covid restrictions are really starting to get me down. Last March I thought we would have been back to normal by June 2020.

...R

My creative juices are way down thanks to Covid
But we seem to be seeing a slight downward trend there so maybe there is hope on the horizon.

ballscrewbob:
My creative juices are way down thanks to Covid
But we seem to be seeing a slight downward trend there so maybe there is hope on the horizon.

Me too. My get-up-and-go got-up-and-went since lockdown. Had the jab last week and it now seems to be coming back a little, as I started a small project yesterday.

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