Merge Multiple Geometries Question

[rubybb]

Hi everyone, still very new to Houdini so I hope someone can help.

I have a sketch model I would like to 3D print (it will eventually be an .stl file). My problem is that the overlapping geometry in my model will cause the laser to overheat and swell (as it tries to print the separate parts in the same 3D space).

How can I boolean or union everything in to one piece of geometry (as opposed to just grouping it)

I've tried putting a cookie at the end of the network but can't seem to get it to work - any ideas?

Many thanks

Green 6 copy.hipnc

[Macha]

That's a pretty mad geometry and I think cookie will not work.

One idea is to convert it to a particle fluid surface. Another idea would be to use a foreach sop and turn each polywire into a sdf and then surface it.

Both methods require lots of time and memory, but should work, especially if you can accept some blobbyness in the final result.

By the way, I'd love to see the final result of the 3D print. It sounds amazing!

Edited November 29, 2010 by Macha

[rubybb]

That's a pretty mad geometry and I think cookie will not work.

One idea is to convert it to a particle fluid surface. Another idea would be to use a foreach sop and turn each polywire into a sdf and then surface it.

Both methods require lots of time and memory, but should work, especially if you can accept some blobbyness in the final result.

Thanks Macha,

I'll try to work out the foreach sop method but could you possibly give me a bit of info on how to convert it to a particle fluid surface please?

Sorry if its simple or obvious but I've only been using Houdini for a few weeks and there's so much I don't know!

I can cope with some blobbyness if I can get this thing suitable for a 3D print!!

Thanks

[Macha]

I'll try to work out the foreach sop method but could you possibly give me a bit of info on how to convert it to a particle fluid surface please?

Use a resample sop on your curves to get the required amount of points. Then append a particlefuid sop and adjust the parameters.

If you want you can add a pscale attribute before the last step so you can adjust scale on height or point number or randomly or whatever. Make sure to include the attribute when you create the surface.

Sorry, I am simulating something now so I can't send you a file, but it is fairly simple to set up so you should have no problems.

[Macha]

I made you an example file. Your geometry is very heavy so I suggest you try it on a small piece before you commit. It probably takes a few hours to mesh, but it will be clean (no intersections).

Green 6 copy.hipnc

[rubybb]

Macha,

Thanks so much for that, I was getting there with the fluid method but nowhere near as tight as that. Going to run it overnight tonight and will see how it looks in the morning.

Thanks again for your help

[rubybb]

Wow! ok after lots of messing around I am almost there with this, so I thought I'd post how I worked around it in case it might be useful to someone else in the future.

Firstly - many thanks to Macha. The particle fluid surface conversion succeeded in removing all the overlapping geometry which was my original question.

The problem then became about the high polygon/face count. When saving out as an .obj or .stl I was looking at file sizes of around 2gb! and which took most of the night to save out. This sort of file size is out of the question for 3d printing.

I tried adding another delete node to remove some of the inner parts of the model and then saved out the model in 8 separate parts (with the aim of putting them all back together in the 3d print software)

This was better and easier to manage but the file sizes were still between 70 and 400mb each which were still causing the 3d print software to crash (magics)

Finally I found a freeware program called meshlab which allows you to reduce the polygon count quickly and easily and has taken my file sizes down to around 4 - 15mb each (for the separate parts).

There is obviously loss in detail using this polyreduction method but as each of the "spines" in my model will print out at around 1mm in diameter, they should still look fairly smooth.

I know this raises issues of how you model in the first place etc. and my geometry was probably unnecessarily heavy, but it was the aesthetic I was after and its almost there.

I'll send the files of to print today or tomorrow and will post the results should anyone else be interested in seeing how it came out!

[Akabane]

For reducing the polycount you can also try the

polyreduce sop

It does a really good job in most cases =]

Cheers, and cannot wait to see how it will print out!