1. #1
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    Default 3D Print Post Processing Tip

    Hello fellow ZBrushers,

    I want to share a post processing procedure I came up with for cleaning up 3D print build lines which also provides a nice paint ready finish for acrylic paint. I built an FDM machine last spring in order to prototype my models and get a handle on 3D printing before investing in a higher resolution machine or having prints done by a printing bureau. I printed this model at 100 microns, it took about 18 hours and is 5 1/2 inches tall.



    Borrowing from my old-school paint on canvas days; I grabbed a couple of palette knives and a jar of modeling paste. If your not familiar, modeling paste is a mixture of acrylic base with marble dust. I apply it with the palette knife much like a dry wall installer applies joint compound to sheet rock. I scrape off any excess while it is still not quite dry. If done carefully this fills the gaps between layers while still retaining detail.



    Modeling paste is easily sanded and non toxic so you can achieve a smooth surface with not a lot of effort. It is also good for filling in problem areas on prints too. In the image below you can see where my hot end clogged (a story for another time) but suffice it to say I was a able to stop the print clear the clog and finish printing. However it left a sizable gap and modeling paste came to the rescue to fill in the space. You can see the difference in the before and after images below. It could use some more cleaning up but I think it gets the idea across reasonably well and the color of the modeling paste is brighter than the PLA filament I used.



    Give it a try, I hope you find this process useful.

    Happy ZBrushing!

    Dave

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    Default

    Such a helpful share, Dave! Got some new tips to apply on my next 3D printing master piece. What material did you use here, btw?
    3D2PRINT- Creating the 3rd Dimension

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    Thanks @edjennings. The print was done in PLA.

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    Default Tinting the paste?

    Thanks for the tip, I usually use bondo spot filler. Can the paste be tinted to match the PLA color? I find that some finishes on the raw PLA prints are really nice and I would rather not paint the whole model, but preserve the appearance of the PLA.

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    Yes you can add acrylic paint to color the modeling paste to whatever tint you desire. Although I haven't tried to match the exact color of a filament it's possible but likely easier said than done.

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    Default File split up for print

    Dave,

    Great post, could you talk a little about the basic process you used to break up the print into successful chunks? Do you do all of the splitting and such in Zbrush or a combination of things.
    Thanks,
    Q

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    Hi Quade, everything was done in ZBrush.

    My goal was to slice the pieces in such a way as to eliminate the need for support material. To that end any unsupported angle was no shallower than 45 degrees.

    Since the face is the most important feature I made sure to rotate the model so the tip of the nose and chin were pointed straight up the build axis. Then I could make decisions regarding slices for the model. Slicing was done with the Slice Curve Brush.

    As I recall, I duplicated my subtools and then merged the duplicates into one subtool and Dynameshed with blur at 0 and Project turned on, and a high resolution setting (I believe for mine it was maxed out), then made it one polygroup.

    Then I used the Slice Curve Brush which as a byproduct gives you new poly groups. I then split the groups and closed the holes. Then used Decimation Master to reduce the poly count on each subtool so its easier for the printing process to handle.

    By slicing at a 45 degree angle I was able to rotate each piece to the correct orientation for the build axis by typing in the correct rotation angle along the appropriate axis in the deformation sub pallet.

    I hope this helps.

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    Thanks for the detailed response. I am currently trying to find the best way to cut up a complex model so that I can get the most stable and quality print without creating a huge seam or too much scarring from supports.
    I was slicing my model in meshmixer after combining all the subtools and decimating my model as one piece. It seems it makes more since to decimate each individual printing component separately hence the reason to cut it up in Zbrush.
    I assume that if you dynamesh with 0 blur and project on you get a more faithful representation of your high poly model. I was dynameshing after merging then turning dynamesh off once I had a one piece model, bumping the subDs back up deleting lower then decimating. Whewwww. Sorry for the long explanation. In any case, it sounds like it is best to stay with a hi res dynamesh and then cut up the model correct?
    Back I go to re-think how to cut up my model.

    Thanks,Q

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    It sounds like you are on the right track. I personally prefer to do all my prep in ZBrush. It really boils down to a visual analysis of what will work for a particular model combined with you're experience with your printer of choice. The finishing work and painting is what really takes it to the next level. This model of an Egyptian oil lamp was printed finished and painted as a prop for an indie film project.


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    Default 3d Printing and post processing

    That looks great. I am trying to achieve a bronze look as well, I used a copper base coat and followed up with oil paints over the top, but I think I need to incorporate some of the blues and greens that occur as well. I am working on a more complex scene than the one attached here, but I think I will try to split the model at the legs so that the seams don't end up going through the body like I have here. I used a good bit of bondo and some work with the soldering iron to try to blend it, but feel like I would prefer to reprint it with the seam in a less visible location.

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    Nice model and 3D print.

    Here is another handy tip for "welding" the pieces together. If you have a Dremel tool and the 1/16 collet for holding 1.72mm filament.

    You can cut a small piece of filament so that it sticks out of the end of the Dremel about 3/4 inch +/-.

    Then spin up the Dremel and lightly apply the spinning filament to the seam on the model and when it starts to melt use it like an arc welder.

    I use either a bit of super glue to hold the pieces together before welding, or do what real world welders do and spot weld in various places to get the pieces to line up then finish welding all along the seam.

    This is how I attached the various pieces of the Egyptian oil lamp together and in this case I wanted it to look welded so I didn't smooth it out with modeling paste and sand for a seamless look. The exception being where the two pieces of the handle come together and where the spouts attach to the bowl. In that case I wanted it to appear as seamless as possible.

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    Default welding the seam

    Thanks Dave,

    I will give that a shot this afternoon. I have a new one fresh off the printer waiting to be put together. I was using a soldering iron and bit of filament the other day to fill a gap with fair results. Then filling with bondo spot putty and sanding. One other technique was also suggested to me that I will try. If it seems promising I will let everyone know how it works.

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