Author Topic: Does anybody here export STL or OBJ format for 3D printing?  (Read 563 times)

BlankMan

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Does anybody here export STL or OBJ format for 3D printing?
« on: December 01, 2017, 08:42:40 AM »
I've had ongoing problem exporting STL and/or OBJ files using DesignCAD 3D Max doesn't matter the version. I was really hoping 2018 would fix things but that is not the case. I have been in contact with Kevan almost perpetually. I'm told the triangulation algorithm has problems.

I basically cannot reliably export a STL or OBJ that will slice and print correctly. (I use Simplify3D.)

I don't see posts here on the subject so that makes me wonder if people are using it the way I'm using it, for 3D printing. With all the problems I have I would expect to see more mention of the problems here.
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Lar

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #1 on: December 01, 2017, 12:41:50 PM »

Do you convert regular Solids to Solid Surfaces? ...and then maybe "Triangulate Surface"? Maybe check "Is Solid Watertight" first (the latter 2 found under Edit menu>Selection Edit>...  The former under ...>Convert).

I don't 3d print but I often convert to Cinema 4D so I face the challenges of converting dcad's not-limited-to-3-or-4-points surfaces and neighboring-surfaces-not-necessarily-sharing-a-common-edge solids to other 3D apps. Also, I don't know about you guys, but my dcad models, all versions, usually do not have connecting common points when you zoom way down. Maybe that has something to do with it.


You may also have to rotate the model 90 deg on the X axis so it stands "up" and not lay flat on its face when imported.


If none of the above works, and since I intend to be 3d printing sometime in the near future, can you attach a simple small model. I would like to export it to C4D and STL it there to see if you can get it printed.


Lar

BlankMan

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #2 on: December 01, 2017, 02:16:58 PM »
Thanks for the ideas and yes. Many attempts at all that you mentioned with Kevan's guidance.This isn't new, I've been 3D printing for years now and these DC3 problems have been around all along. I'm just wondering why I haven't really seen them mentioned here, and yes, I'm a lurker...

And yes done the watertight test and DC3 2018 even tells you now when you're doing a Solid operation if/that it's no longer watertight. And Keven has shown me how to fix T junction triangulation errors. But other things I do not know how to fix.

And when the objects are large and the triangles are small and extend from one end of the object to the other and the short side of the triangle is only pixels in length when zoomed in it's not easy. And that's on a 32" 4K monitor.

And I've rotated in DC3 before export because the axises are different in the 3D slicer/printer world and you can always rotate in the slicer to print in any orientation you so desire.

I'll do even better then that, I'll give you the dcd and an image of what it looks like in DC3 and in Simplify3d, a well regarded slicer. Stay tuned, more to come...

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Lar

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #3 on: December 01, 2017, 02:40:50 PM »
Ok, I'll be here waiting...

BlankMan

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #4 on: December 01, 2017, 07:01:13 PM »
Here ya go.

The first picture is now they look in DesignCAD 3D MAX 2018. The second picture shows the OBJ export on the left and the STL export on the right in Simplify3D 4.0.

They should look solid in Simplify3D just like it does in DC3. The fact that they don't is due to mistakes in the triangulation which Kevan has told me DC3's triangulation algorithm has problems. Obviously eh...





The dcd is here
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Lar

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #5 on: December 02, 2017, 11:35:31 AM »
BlankMan, your file link opens as binary text in my browser ...and I actually tried pasting it to a word processor to saving with a dcd extension but only a few lines got paste in.
You have to attach the dcd file using "+Attachments and other options" below the white typing area.

I was wondering why it exported so horribly but now I see the whole thing got flipped along dcad's Z axis. Looks like the common problem with dcad's exporter not knowing where the holes are BUT if this were the case then converting to Solid Surfaces and Triangulating should fix the problem. My guess at this point would be you have to "No-Last-Point-Slice" each of the Solids down their middle, along the Z axis. "No-Last-Point-Slice" means setting all but the last point then pressing enter to end the command so the Solid gets sliced but both sides remain. This way there would be no ambiguities as to what are surfaces and what holes.

I'm not sure if it would then be better to just leave the 2 slices as is or Solid Explode the 2 halves, delete the 2 inner surfaces then Solid Define the 2 halves back into one Solid. I guess the latter would be better otherwise you would have 2 surfaces occupying the same space, which can't happen in real life so the 3D printer may freak out.


Lar
« Last Edit: December 02, 2017, 11:38:40 AM by Lar »

Lar

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #6 on: December 02, 2017, 12:34:25 PM »
I just did a simple hole test with full solids (ie, with true holes), split solids separated and split then re-solid defined. Some were regular solids, some were solid surfaces, triangulated. In all cases the full solids had skinned over holes and all the split solids came over correctly.

A few things came up...
1] Don't do the "No-Last-Point-Slice", because dcad may eff it up. Set all the points to eliminate one side then mirror the other side back on. Note that this only works if the object is symmetrical along the holes. If not then you will have to slice minus the last point then clean up where necessary.
2] It is better to re-solid define the halves back into one solid because the STL will combine all the different dcad solids into one entity anyway (the different parts will still be separated from each other but they will all get selected together). Therefore, when doing #1 above, before mirroring do the solid explode and delete the new edges, then mirror the half, then solid define the complete thing.
3] You can get a preview of how dcad will export the model by duplicating the model and Solid Surfacing the duplicate, then examine to see what gets messed up. The export will probably mess up in the same way.
Lar
« Last Edit: December 02, 2017, 12:41:51 PM by Lar »

BlankMan

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #7 on: December 02, 2017, 02:03:50 PM »
When I click on the link for the DCD file in Safari on my Macbook it downloads.

When I click on the link in Firefox in Windows 7 a window pops up asking me if I want to open it or save it.

When I click on the link in Firefox in Linux a window pops up asking me if I want to open it or save it.

I do not think the problem lies in the link to the DCD file. If it opens in your browser instead of downloading I would say the issue lies in your browser.

No it did not get flipped on the Z axis in DesignCAD by accident, as I stated earlier I rotate it on the Z axis before exporting because the Z and Y axis in the 3D printing world are flipped. That way when imported into a 3D slicer it is properly orientated.

As I stated earlier switching to Solid Surfaces does not solve the problem. Kevan had me trying that ad nauseum.

I'm not familiar with "No-Last-Point-Slice", could you maybe do that and see? You can give me that modified DCD file or the OBJ and/or STL file and I can see.

And actually I'm not understanding what you are referring to by doing this slicing. It needs to be a single mesh with only external triangles. If I'm understanding what you're saying slicing it would create solid layer inside and not be one mesh with triangles only on the exterior.

1) the two small "T" end plates are symmetrical on one axis, the larger objects are not symmetrical on any axis.

2) see #1

3) I have converted to surface, triangulated, it does not looked screwed up in DC3. I can post a picture of that to show you if you like.

Thanks for the ideas, I have been dealing with these export problems for over 2 years, with Kevan, so far there is no magic potion.
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Rob S

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #8 on: December 02, 2017, 02:37:26 PM »

THE dcd  file downloads fine for me using seamonkey (mozilla based browser) by clicking on the word "here" either to save or to open directly with DCAD 2018

I know little to nothing about stl or 3D printing, so not much help there.
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BlankMan

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #9 on: December 02, 2017, 03:13:26 PM »
Thanks for testing it Rob.
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Lar

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #10 on: December 02, 2017, 03:50:20 PM »

Blankman, I had absolutely no issues STL exporting from dcad and opening in Cinema 4D. My STL file from dcad is attached as well as a re-STL from C4D. Load them into your3D printed app and lets see what happens with each. The attached image is how it rendered in Cinema 4D. I only jazzed up the lighting and shadowing because without them the details got lost.


Lar
ps, I used Chrome to download the file. I suggest you just use the forum's attachment to upload stuff (unless the forum don't allow that file type).
pps, just in case you don't know... click on the image thumbnail below to view full size, click again to shrink it back down.
« Last Edit: December 02, 2017, 04:27:23 PM by Lar »

Lar

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #11 on: December 02, 2017, 04:13:06 PM »

ppppps... one change I did make was changing the foot based units to inches, since the foot based export seemed to be tiny. However, the dcad size of 128", 50" and 15" is very large, if this is a keyboard's spacebar.


Lar
« Last Edit: December 02, 2017, 04:15:49 PM by Lar »

BlankMan

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #12 on: December 02, 2017, 04:41:59 PM »
I don't how you managed to get those dimensions. The thing is like 9"x2" and with the end plate in the drawing is around 10-3/4"x2", so the two are 10-3/4"x4". That's how it's drawn in DC3 and that's how Simplify3D sees it and that's how the 3D printer sees it and it fits on it's 12"x12" bed. 128 inches? A 12-1/2 foot 3D printer? I don't think so... LOL
« Last Edit: December 02, 2017, 05:19:19 PM by BlankMan »
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BlankMan

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Re: Does anybody here export STL or OBJ format for 3D printing?
« Reply #13 on: December 02, 2017, 04:54:56 PM »
Oh and just because it looks OK in 3D viewer software does not mean it's ok.3D viewer is very forgiving and doesn't show things.

This is how the OBJ in the image above looks in a 3D viewer app. Looks just fine here don't it?

« Last Edit: December 02, 2017, 05:26:56 PM by BlankMan »
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 #14 on: December 02, 2017, 05:08:42 PM »
LAR, when I import your STL files into Smiplify3D one is scaled up 64,516% and the other is scaled up 2,540%. Yes thousands of percent. Even when I change the scale of either one back to 100% there is nothing there.

Somehow your changing the size to 128" probably made them too big and Smiplify3D knows the printer has a 12"x12" bed.

Now here again, going back to what I said about 3D viewers being forgiving one of my 3D viewer apps can load it and display it.
« Last Edit: December 02, 2017, 05:27:38 PM by BlankMan »
Newbie? Not.
Been using DesignCAD 3D since ~1990
Still have version 4 floppies...