Author Topic: Does anybody here export STL or OBJ format for 3D printing?  (Read 565 times)

Lar

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #15 on: December 02, 2017, 05:18:15 PM »
That's the size in the file I downloaded, changed to inches. See attached image.

Lar

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #16 on: December 02, 2017, 05:28:41 PM »

Here is the correct size STL with the dcad file set to feet...

Do you draw as  Feet, or Unitless? I think maybe you draw as unitless but my dcad is set to open unitless drawings as feet. So when you draw 1 unit in your dcad it opens up as 1 foot in mine. That's only 12 times bigger so I don't understand the thousands of percent increase. I guess when I get my own 3D printing system I will understand why that happens.


Lar
ps... yes, you do draw as unitless. I can see it in your first image from your dcad file...
... maybe you should try using foot inch units to see if unitless is why you have problems exporting.
« Last Edit: December 03, 2017, 07:26:58 AM by Lar »

adriank

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #17 on: December 02, 2017, 07:56:11 PM »
Same as Rob said, I know nothing about 3D printing - I do however work a lot with laser cutting and routing production of my designs.

I think it was the good Doctor, Phil (Dr. PR) who alerted us to a good trick to clean up solids using solid subtract.
If you make a new solid object that is completely detached from your solid (so you don't cut lumps off it) and then 'solid subtract' it from the solid you want to clean up it very often fixes the issues.
If you have not tried that it may be worth a go.

I also opened your drawing without any problems - it is drawn 'unitless' and measures approximately 10 units x 2 units.
I exported the file to Sketchup and it imported perfectly fine (albeit with a loooong list of internal fixes reported) and it measures 10" x 2" in Sketchup by default.

The machine shop that I work with for CAM work can use Sketchup files to work from (although I have no idea what programs he uses for machine code) & it may be worth pursuing that angle too?

Adrian

Dr PR

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #18 on: December 02, 2017, 09:31:26 PM »
That Solid Subtract trick usually cleans up duplicate surfaces and internal surfaces. It also combines all polygons that lie in a common plane, with common edges. That reduces the number of facets in a planar side to a polygon.

I usually just draw a cube/box somewhere off to the side of the solid to be cleaned up - being sure the two solids do not overlap. Then I subtract the box from the solid I want to clean up.

That's with the original Solids. I haven't experimented much with Solid Surface objects.

Phil
DesignCAD user since 1987

paul craig

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #19 on: December 03, 2017, 04:31:01 AM »
some of you will remember that I produced some things about 4 years ago, and used a couple of third party programmes to convert to "proper" watertight,.
One was a Canadian free ware type product, but I found it difficult to use, not least because of the difficulty in zooming close enough to see the holes.
Also there used to be a German free service whereby they converted into watertight as long as they could keep and promote your file for a while, that
company seems to have been sold to Microsoft, so it is no longer inexpensive methinks.

There was then my attempt to create a locomotive chimney in 3d, with the various sweeps, I have found that thread http://forum.designcadcommunity.com/index.php?topic=5208.0
but it did not and does not answer directly the questions of the poster. I, having downloaded the latest version of DCAD, tried to replicate what we did then,
so far without much success with the solid patch. I am doing something wrong again, which is basically down to my lack of practice in 3d work, since I spend so much time
creating etching artwork.

I have attached a couple of the files I produced before to show what I was able to achieve, and get printed by a friend, and not at Shapeways for instance.

May not help, but gives you an idea of what was achieved 3 or 4 versions ago.

Paul

paul craig

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #20 on: December 03, 2017, 05:17:47 AM »
couple more  drawings originally from 2013, each of which we have actually printed in 3d more than once.
What is fascinating is the upgrades in the software for the printers has made it a much smoother and
more accurate print. However, as before there was need for post dcad modification.

paul

Lar

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #21 on: December 03, 2017, 07:24:32 AM »
That Solid Subtract trick usually cleans up duplicate surfaces and internal surfaces. It also combines all polygons that lie in a common plane, with common edges. That reduces the number of facets in a planar side to a polygon.
This may be the 8th wonder of the world, that dcad's everyday regular Plane entity can have any number of points. However, to the rest of the 3D world out there it is toxic. They can only deal surfaces fragmented into 3 point segments. Why? Because a 3 point surface is always planar... it will never have any of its points out-of-plane, no matter how you move any single point around, so they require less calculations.

Thing is, though, that dcad itself has proven that this system of fragmentation is better because while dcad, after all these years of 3d improvement, still struggles with real time shaded/hidden line orbiting and cannot do non-destructive booles, these other 3d programs can do such things without batting an eye. And you can't blame it on costs because free 3d games have real time full color rendered animations, including shadows and reflections.

Now, to get back on topic, BlankMan's issue stems from dcad's own export algorithm being intoxicated by dcad's own polygonal Plane method. DT&Co's answer to this is the new Solid Surfaces. I don't know why BlankMan is having trouble with his exports, but when I export Solid Surfaces they usually go over ok.


Lar

BlankMan

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #22 on: December 03, 2017, 08:27:47 AM »
Lar, I looked, yes I'm set to unitless. Usually I have the units of measure set to inches, in 2016 and now in 2018 I left it unitless but I always draw in inches and don't open any drawings but my own so to me it's a moot point. So the fact you open unitless as feet it the reason why you see it so large.

Hey Adrain thanks. I have entertained opening my drawings in other apps and even tried that at times to see if that would be a ways of fixing DC3's export triangulation problem. I'm familiar with Sketchup but never used it. When you say it provides a list things to be fixed can it fix them or are they easily manually fixed there?

Adrian, Phil, oh yeah I caught on to the Solid subtract issue. I do my drawing via BasicCAD especially in the prototype stage using variables so that when I test fit and have to change something I change the dimension in the associated variable and rerun it and I'm done. So I'm well aware of what causes the triangulation problems that DC3 has.

It's not limited to SolidSubtract, I drew something last night that a SolidAdd was the cause of the problem. It is also highly reliant on the order things are done. Do something near the end, it wipes out the drawing (export triangulation wise), move the operation to the beginning and the exact same operation will be fine. I spend a lot of time finding the right order to use.

Phil, that's a nice trick (SolidSubtract), I'll give 'er a try.

Lar, even with DC3's "Use triangles" checked in the OBJ export there are still problems. And either do I, converting Solid to Surface and exporting provides the same exact broken OBJ and STL exports either way.

Thanks all, am appreciating the help.
Newbie? Not.
Been using DesignCAD 3D since ~1990
Still have version 4 floppies...

BlankMan

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #23 on: December 03, 2017, 08:55:31 AM »
Here is my latest endeavor. How it looks in DC3 and the exports imported into Simplify3D, the OBJ on the left the STL on the right.


Newbie? Not.
Been using DesignCAD 3D since ~1990
Still have version 4 floppies...

BlankMan

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #24 on: December 03, 2017, 10:28:11 AM »
Phil I tried your SolidSubtract trick, didn't make a difference.
Newbie? Not.
Been using DesignCAD 3D since ~1990
Still have version 4 floppies...

Lar

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #25 on: December 03, 2017, 10:45:00 AM »
BlankMan, 2 things...

1] Could you try the smaller size STL file I uploaded in my reply #16 to see if the size is ok in your 3d printer app?

2] Does your 3d printer app have a feature called 'Backface Culling'? If you have it and its on it will cause all the surfaces whose normals are pointing away from the camera to become invisible. it shouldn't affect the actual geometry of the model, though, so those surfaces will still be there, just invisible (because, if you spin the model around the ones that are now visible will become invisible). Its purpose is to speed up the display but if any normal that should point outward (as every outside surface should) is actually pointing inward then that surface, even if its facing the camera, will be invisible.

In dcad you can go to Shading dialog>Open-GL>Normals to see which surfaces point away from the camera. You can also flip the normal in dcad but it can be very tedious. If this is the case then maybe your 3d printer app will have an easy way to correct the normals.


Lar
« Last Edit: December 03, 2017, 10:50:49 AM by Lar »

BlankMan

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #26 on: December 03, 2017, 12:01:24 PM »
I updated my Blender by downloading the latest version and installing it and I was able to fix the horrendously problematic DC3 exported OBJ file and then export it as an STL.

Look at the RESULTS!!! Something I can actually print!!! Oh My God... Do I sound happy? Yes. I. Am.

Looks like DC3's programmers could learn something from Blender's Open Source crew.... After all, they were able to fix this mess...

Newbie? Not.
Been using DesignCAD 3D since ~1990
Still have version 4 floppies...

BlankMan

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #27 on: December 03, 2017, 12:27:18 PM »
Lar, here is your STL imported into Simplify3D. The sizes appears to be correct however the mesh is still pretty screwed up.

Newbie? Not.
Been using DesignCAD 3D since ~1990
Still have version 4 floppies...

Lar

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #28 on: December 03, 2017, 03:07:06 PM »

BM,
My vote: this is not a dcad problem. Cinema 4D and SketchUp opens it ok. The issue obviously lies somewhere within your systems.


Did you try the "Backface Culling" idea I mentioned previously?

Lar

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #29 on: December 03, 2017, 03:19:09 PM »

BM, Simplify 3D does have Backface Culling, as seen here in the attached snippet captured from S3D's forum (https://forum.simplify3d.com/viewtopic.php?f=23&t=5932&start=10). Please could you check to see if it is turned on?


Lar