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Titon
10-03-2017, 12:25 PM
Hi,

I recently gotten into the 3d print world and low and behold discovered how completely off lightwave measure scale is off.

Has anyone come across a way to fix this issue or would it have to be written into a new version?

I even noticed while using my Modo it's scale is not correct.

Thoughts?

10-03-2017, 12:55 PM
Sir/Ma'am,
You are incorrect.
With the stl exporter, I can get things quite accurate. My class does a 2cmx2cmx2cm box as our first print of the year. The 2% shrinkage stated by many forums for materials is the only thing I've had to compensate for. And even that can be done at print time.
On the CNC, same deal: what comes out of lw measures the same as what's in LW.

Talk about your process because something is amiss.

Greenlaw
10-03-2017, 01:00 PM
It's probably the unit difference between meters vs millimeters. If the object is coming into Modeler way too large, try scaling it down to .01 or .001. Depending on the object format and how you're loading it, you may be able to set this at load.

When exporting an object for 3D printing using Modeler's Export STL tool, setting the axis to Z-up (the default,) and Export Units to mm works for me.

If you're talking about something else, I think we need more info and examples.

rustythe1
10-03-2017, 02:20 PM
yes, Lightwave uses real world measurements, (I think there is a statement somewhere that says its actually the only 3d app that actually does) all other apps use units to define, then you tell the app what that unit means, in lightwave under "display options" you can chose what a unit means, default is Metre so you have to change this to MM to match things like netfabb, or you can model as if Meters are MM i.e 1 metere = 1 mm, lightwave is actually very accurate once you get around it and ive never had an issue working on very small FUD parts

Ztreem
10-03-2017, 04:29 PM
This happens all the time when transfering 3D data between apps even accurate CAD apps. I get CAD models from the US sometimes and I have to convert everything from inches to milimeters otherwise everything is screwed. LW workes and saves in meters most other apps works in milimeters so you have to multiply or divide by 1000 to get the right scale. Model formats usually don't save if its in milimeters or meters it just save the value, like for example 1x1x1 cube. In LW this will be 1m x 1m x 1m in another app it will be 1mm x 1mm x 1mm. Thats just the way it is.

Titon
10-03-2017, 04:52 PM
I model in inches. I can take something i modeled supposedly to scale in lightwave and transfer to say Rhino and have it measure completely opposite. Most time transfering to Rhino it comes in so small can't even see it.

I have converted Lightwave units to English and i am using inches. I can model a 1"x1"x1" cube and save it out and importing into Rhino it comes in at .03. Now i can build that same cube 1"x1"x1" in Rhino and import it back to lightwave and lightwave says it's 3'x3'x3'.

What i am saying is there should not be such a drastic difference between softwares when it comes to accurate measurements. The company i work with says the cube built in Rhino is correct but the cube built in lightwave never comes in correct.

Now either i still do not have lightwave configured correctly or something is definatly amiss...

Ztreem
10-03-2017, 05:08 PM
I remember somewhere that LW always saves i meters even if you change to inches, I'm not 100% sure on this one. But as you get 0.03 in rhino when its 1 in LW indicates that. As 1 inch is 2.54 mm and if you have 0.0254 and round it up it gets 0.03.

Imageshoppe
10-03-2017, 05:59 PM
I've been printing the ever-loving-daylights out of things since I got a Creality CR-10 and a smaller Ender 2 printer, using Simplify3D to slice. Dead accurate scaling, follow these simple steps...

1.) Use whatever scale in LW you want, metric or English, doesn't matter. I often switch between them and work bi-directionally, using the numeric fields for conversion. It's all good...
2.) Export via the STL exporter... the KEY FOR SUCCESS is to using 1000 as the multiply scale factor in export units. This is the proper multiplier to bring things up to real world size.
3.) If you run into any non-manifold issues in your slicer, despite your best practices with your modeling techniques, pass the STL file up to this site; will fix any issues and give you back a file that will print perfectly...

https://service.netfabb.com/login.php

That should get you started...

Regards,

Jim Arthurs

Titon
10-05-2017, 04:56 AM
Jim,

I was able to export a simple .stl box using your method and it did load into Rhino as a 1" box this time. Thanks for the advice. Do you have any advice as how to go about scaling it properly exporting to say an .obj file? I tend to model and like to test my progress for errors before fully exporting and it would be nice to scale the same way with and obj file.

Don

Imageshoppe
10-05-2017, 08:30 AM
Jim,

Do you have any advice as how to go about scaling it properly exporting to say an .obj file? I tend to model and like to test my progress for errors before fully exporting and it would be nice to scale the same way with and obj file.

Don

Can't speak for Rhino, but for Simplify3D the proper LW OBJ export scale is 100000.0 %. This option is located in LW under General Options/OBJ. It seems to come into S3D rotated back 90 degrees on pitch, but otherwise correct.

Reset this scale value back to 100% before exporting an OBJ to Zbrush, if you work with that program as well.

Hope that helps,

Jim Arthurs

10-05-2017, 08:34 AM
You should try what you are speaking of; I believe you will find you can.
That is to say, on some obscure layer, scale your object appropriately and export the layer as an obj. See if it worked.
The formula for sizing should work for things in and out of lw.

jeric_synergy
10-05-2017, 09:28 AM
Jim, that's some GOOD info to have in hand. THANKS MAN.

ConjureBunny
10-05-2017, 09:40 AM
Hi Titon,

(I'm kinda cross-posting this, but this is a slightly different issue from the other thread)

This sounds a *lot* like a scale bug in the original LightWave STL algorithm.

Try using my free ExportSTL script instead.

I wrote this back in 2013 to correct a few really minor math problems in the earlier algorithm, and to fix Mac path compatibility.

One important, vital note: turn off symmetry. For some reason this makes your print wonky.

I use this script at least once a day. I might have a 3d printing 'problem', now that I think about it. Wait, the only problem I have is running out of filament. But anyway, it works great. Straight out of LightWave. And if you have any problems with it, let me know, and I can fix it

http://www.liberty3d.com/2013/03/freebie-export-stl/

-Chilton

Titon
10-05-2017, 12:05 PM
Hi Titon,

(I'm kinda cross-posting this, but this is a slightly different issue from the other thread)

This sounds a *lot* like a scale bug in the original LightWave STL algorithm.

Try using my free ExportSTL script instead.

I wrote this back in 2013 to correct a few really minor math problems in the earlier algorithm, and to fix Mac path compatibility.

One important, vital note: turn off symmetry. For some reason this makes your print wonky.

I use this script at least once a day. I might have a 3d printing 'problem', now that I think about it. Wait, the only problem I have is running out of filament. But anyway, it works great. Straight out of LightWave. And if you have any problems with it, let me know, and I can fix it

http://www.liberty3d.com/2013/03/freebie-export-stl/

-Chilton

Thanks for the advice. I will attempt your plugin. Thing is i haven't done much exporting of .stl files from lightwave. I like to check with another software for errors before converting to .stl which i find all the time. If i can properly export .obj then i should be good to go. It worked Jim's way through the native .stl plugin in lightwave but again i like to check before i convert. ALthough i still could export and .obj and fix the errors. Once i know what errors need repairing i can always just export the repaired .stl right out of lightwave.