projecting toolpaths onto 3D model

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paorawiremu
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projecting toolpaths onto 3D model

Post by paorawiremu »

I am having some trouble projecting my vcarve onto an irregular surface. Would love some help!

I'm using the Regular Grid Importer gadget to make the model from a point cloud (generated by a probe).

This is what my preview looks like on a flat surface, and is correct:
vcarve1.JPG
This is what my preview looks after I project the vcarve toolpaths onto my 3d model. When the machine cuts it looks like this - waay too deep into the material:
vcarve2.jpg
I'm not sure whether I have my settings correct. Perhaps I need to adjust the distance the model sits above the material as well (in material setup)?
vcarve2b.JPG
vcarve2c.JPG
Here is my point cloud:
pointcloud 28 10.txt
(2.22 KiB) Downloaded 49 times
Thanks!

paorawiremu
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Re: projecting toolpaths onto 3D model

Post by paorawiremu »

Theoretically the bottom left of my material should be 0 on the z axis. This is the point to which all the positive and negative z axis points in the point cloud are relative.

Perhaps I'm totally wrong, but my theory is that the way this 3D model projection works is by making the highest z axis point on the model, 0, and working backwards from there, which is creating a negative z axis offset.

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Adrian
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Re: projecting toolpaths onto 3D model

Post by Adrian »

Did you run the 3D toolpath preview as well? To me it looks as I would expect if you had run the v-carve toolpath on it's own without previewing the underlying model.

If you switch to 3D View (not toolpath preview) and move the mouse over the model you can see the z height displayed on the bottom status bar. The top left is 0, bottom left is 2.26, top right is 2.6 and bottom right is 3.5, centre is about 2.5.

paorawiremu
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Re: projecting toolpaths onto 3D model

Post by paorawiremu »

I've gone to the 3D view and looked at the z heights. The lower left corner of the material reads a z height of -1.29mm. This should be my 0 z-height (as shown on the point cloud).

I lifted my spindle by 1.29mm and ran the code and it gave a perfect result. However, it would be great to do this within Aspire, rather than cheating.

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Adrian
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Re: projecting toolpaths onto 3D model

Post by Adrian »

I guess you must have changed the position in model or some such as no point is below 0 when I do a straight import with the gadget.

paorawiremu
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Re: projecting toolpaths onto 3D model

Post by paorawiremu »

Thanks for replying. Hmmm, I'm so confused.
Can you run through your process of importing the grid?
Do you need to turn it into a solid shape?
I thought I could get it to work, but I'm still having inconsistent results.
I made a larger piece that turned out pretty well but I have one in the machine at the moment that doesn't look so promising.
DSC_0016 3b.jpg

paorawiremu
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Re: projecting toolpaths onto 3D model

Post by paorawiremu »

This is my latest point cloud.
pointcloud 11 4 edited.txt
(20.95 KiB) Downloaded 32 times

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Adrian
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Re: projecting toolpaths onto 3D model

Post by Adrian »

I just loaded it via the gadget and left it at that. I didn't do anything else to it.

paorawiremu
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Re: projecting toolpaths onto 3D model

Post by paorawiremu »

Hmmm, do you position the model in the material with a 0mm gap above the model?
material.jpg

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Adrian
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Re: projecting toolpaths onto 3D model

Post by Adrian »

Don't forget that the Z values show when you hover the mouse depend on where you have the z-zero set. I always work with the z-zero at the bottom so all my z values are positive. If you work with it on the top then your z-values will be negative.

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Re: projecting toolpaths onto 3D model

Post by paorawiremu »

So when you say you work with the z-zero on the bottom, you mean you set it to the 'machine bed', rather than the 'material surface'?

The designs I've been cutting are working to a degree. It seems that it is lifting too high in the raised areas and then cutting too deep in the sunken areas. Do you know what could be causing this?

I am v-carving so it could be a bit settings issue...

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Adrian
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Re: projecting toolpaths onto 3D model

Post by Adrian »

Yes, z-zero on machine bed. The bottom dot in the Job Setup picture.

If it's cutting both too high and too low that seems a bit odd to me. I can't think off the top of my head what that could be. Hopefully someone else will chime in on this thread with some ideas.

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Re: projecting toolpaths onto 3D model

Post by martin54 »

I have never used the gadget so not sure how it works but I have projected quite a bit of stuff onto 3D models.

What's your process? Are you starting with a flat piece of stock, machining the model & then projecting the vcarve onto that model or are you starting with a pre-spaped piece of stock that already has a 3D design cut on it?

The only way I can think for it to be cutting the way you describe is if you were using a pre-shaped piece of stock & the model that has been created for that doesn't match properly.

It actually looks from your picture like a flat piece of board so I don't fully understand the project onto 3D model unless that is how the gadget works. :lol: :lol:

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Re: projecting toolpaths onto 3D model

Post by adze_cnc »

paorawiremu wrote:
Fri Oct 28, 2022 3:20 am
Theoretically the bottom left of my material should be 0 on the z axis. This is the point to which all the positive and negative z axis points in the point cloud are relative.
Here’s where the process breaks down. Once the point cloud is processed into Aspire via the gadget the Z values don’t corespond on a one-to-one basis with the Z values in the model in Aspire.

By setting the z-zero to the material surface in Aspire and by having 0mm above the model in the Material Setup dialog on the toolpath tab you are saying to the software that whatever point(s) in the point cloud that had the largest positive Z value now have a Z of zero (i.e. the surface of the theoretical material block in Aspire),

The image below is the point cloud brought into Rhino 3D. The two points in the lower right connected by a short line segment are the highest points in the cloud. They will corespond to the material surface (Z zero) when impotted into Aspire via the gadget:
 
rhino.png
 
If you set the z-zero on your machine to ether of those points your file should (will) cut properly as you’ve matched the z-zero in the software to the z-zero on your surface. No need to mess around with offsets here and there.

paorawiremu
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Re: projecting toolpaths onto 3D model

Post by paorawiremu »

Hi Martin54,
I have an existing surface, which can't be levelled, that has some irregularities - they are very subtle, only a few mm, but they make a difference to an engraving.
Captureprobeb.jpg
I use my probe to make a surface map as a point cloud, which the gadget imports and turns into a model.
I am then projecting my design onto the 3d model so that when it cuts, it will negotiate the humps and slumps correctly.
Here is my model with the image projected on it in Aspire:
313115631_501833708328943_2514975141790193576_n.jpg
The problem I am having it that the lower areas (see that dark patches), are cutting too deep, and the lighter areas cutting too high.

Hi Adze,
Thanks so much for your model. Yes, this is how I was expecting it to work. I have been lifting my z-axis and zeroing to the highest point of my material surface, but I've been calling this offsetting, rather than zero-ing it to the highest point. I've been looking at how much my original z-zero dropped to see how much to lift it.

I've been using 30degree and 45degree engraving bits, so I will experiment with a few different pieces to see if they make a difference.

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