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<p>First, thank you all for your responses. I became even more enthusiastic about X3D after I took knowledge of the cura import plugin, this is just a few days after I myself submitted a small contribution to cure. I subscribed to the PR immediately. I saw that it was already accepted and merged, and I will be testing it as soon as I get the compiled version.</p>
<p>I knew that Cura is internally based in triangles, I understand that this applies to all 3D Printing slicers on the market currently, and I do not think the NURBS support is something highly demanded now, but I am quite convinced that it will be in the near future. There is also some discussion about support of ARCs - and most firmware like marlin and repetier already support the gcode arc commands (G2 and G3). The slicers that support it seem to be using the arc commands from "inferring" the arcs from the triangles -- Simplify3D was doing that before version 3.0 but dropped this feature because it caused problems. However I think a comeback is likely, because the artifacts caused by interpolation and/or approximation doing in the modeller or the slicer are becoming more evident as the techniques for 3d printing improve.</p>
<p>I also understand that Blender has a relatively weak NURBS support, as in having very few tools to deal with it - I took a few days to learn how to close a single NURBS cylinder - but I also think that it is because it is not very used, not very needed, and that will change as elsewhere in the 3D printing stack "real curves" are needed. I might even try experimenting with the current x3d import/export plugin to add the nurbs components. As far as I saw, it is a straightforward 1-to-1 mapping.</p>
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<p>BTW, there is something else I could still not find on the X3D standard. 3MF has a slice extension that in practice allows to embed the gcode, or x3g [makerbot format], or slicing code equivalent in the file. Is it possible to extend X3D to support slicing information too? Furthermore, what would be the most convenient metadata to designate special types of material, like support material (that might need to be dissolvable, or coarser, or discarded altogether depending on the 3d printing technology)?</p>
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<p>Thanks again!</p>
<p>Cláudio Sampaio - MakerLinux</p>
<p>Em 18.09.2016 12:22, Alekseyev, Vsevolod (NIH/NIAID) [E] escreveu:</p>
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<div><span style="font-size: 10pt;">X3D support is coming to Cura in the next release: </span>https://github.com/Ultimaker/Cura/pull/914<a style="font-size: 10pt;" href="https://github.com/Ultimaker/Cura/pull/914">https://github.com/Ultimaker/Cura/pull/914</a> . There's no support for NURBS geometries, or any kind of curved geometry for that matter. Cura was built with STL in mind, its internal mesh format is a triangle set. I didn't feel like hand-tesselating NURBS.</div>
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<div>Other slicers that are based on Cura code might follow suit. I also have X3D import code for CuraEngine (distinct from Cura proper), which some slicers are using, but haven't submitted it anywhere yet.</div>
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<div><span style="font-size: 10pt;">X3D import/export modules for Blender don't support NURBS. Blender, as far as I know, does support NURBS in some way, so there might be a way to implement import/export with relatively little effort. I didn't explore the possibility so far.</span></div>
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<div><span style="font-size: 13.3333px;">As for the color mixing, I'll let the more knowledgeable people speak of what is and what is not in the standard. </span></div>
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<div id="divRpF371472" style="direction: ltr;"><span style="color: #000000; font-family: Tahoma; font-size: small;"><strong>From:</strong> patola@makerlinux.com.br [patola@makerlinux.com.br]<br /><strong>Sent:</strong> Sunday, September 18, 2016 10:09 AM<br /><strong>To:</strong> x3d-public@web3d.org<br /><strong>Subject:</strong> [x3d-public] Fitness of X3D for 3D Printing?<br /></span></div>
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<p> Hello all, I am a new member, I was just subscribed to this list. I am a 3D printing professional in Brazil (for low-cost, mostly open-source 3D printers). I searched thoroughly through the list archives but could not really find my answer. I am looking forward to try and implement import and export plugins in Blender for a 3d-printing friendly format. I looked into the standards for both AMF and 3MF, and they do not seem really appropriate. 3MF is nice and full of stuff but does not have any kind of curves, splines or NURBS. AMF has curved triangles and also allows you to specify a formula for the curve, but this seems kind of out of hand compared to "real" NURBS. And since some artifacts - specially in the amount of material extruded - appear from the interpolation of triangles to approximate three-dimensional curves, actual NURBS support would be essential for precise 3D prints.</p>
<p> Then I stumbled upon X3D, which is already implemented in Blender. The latest status of the x3d support seems that from 2015: http://www.web3d.org/news-story/improved-blender-import-x3d-scenes</p>
<p> However, it was not very clear to me if X3D, and its blender import/export addon, would support something fit for material mixing. FDM 3d printer extruders with the capability to additive mix of colors are being sold right now, and support for mixing them is already being implemented in firmware too (with "virtual extruders" for the mixing). Both 3MF and AMF have proper support for this, AMF having even coordinate-dependent mixtures support. I have read in the specs that currently X3D only supports subtractive light, and also no gradient or mixing for materials, is that right?</p>
<p> Does anyone else on this list deals specifically with 3D printing? I am not aware of X3D support in any slicer currently. I am curious as to the fitness of this file format for this task. Am I asking too much? Or maybe it just does not fit its intended purpose?</p>
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<p> Best regards,</p>
<p> Cláudio (Patola)</p>
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