Model thickness out of whack

[Olle]

I'm sure I'm missing something simple, but here goes:

I have a model that consists of several components, all with a zero base height and model heights between 0.330"and 0.775". The material thickness is set to 0.800" with zero Z, and when I try to generate a tool path I get a warning saying that "model thickness exceeds material thickness", with the model thickness shown as 0.8034" and "gap above model" as -0.034". I tried to delete the components one at a time and found that one of them is causing this error. The model height on this is 0.7433" with zero base height, and I don't see anything else that sticks out. I used the search function and found a note about adding a zero plane. I did that, and still had the same problem. Then I set the zero plane's combine mode to "merge", and all of a sudden everything appeared to be back to normal, BUT: Now it shows that the modeling plane has moved up to 0.0248.

The "problem component" I identified has been modified several times over by tilting, changing base height etc so I suspect that something is sticking down below the zero plane, thus adding to the total thickness of the model. Still, the height is less than the material, I can't see anything out of the ordinary in the 3D view and it says that its base plane is zero, so I can't figure out what to do about it. Does anybody have any ideas?

[mezalick]

I use the "Replace Below" gadget to cure such problems
http://gadgets.vectric.com/replacebelow.html


Michael

[Olle]

I checked the tutorial, and I'm not sure if it really will do what I need to do. It appears like the problematic component extends below the zero plane, so what I think I need to do is to delete everything below it.

Still not sure what's really going on here, but I copied the component into a fresh model with 0.800 material thickness. When I open the material setup, it says that the model thickness is 0.7433 (which should be correct), but it also says that the modeling plane Z is -0.0282", which is the same number as I see in the original model. Then I created a finishing tool path to the material boundaries to see what would happen. This should cut away everything except for the component, but it didn't cut all the way through. It just left a thin sheet of the material underneath, probably the same thickness as the discrepancy in height (see pictures).

Now here is the weird thing: This is a component that I have tweaked a bit, but I saved the original. When I paste the original into a new file, it shows the modeling plane as zero. When I paste the problem component into the same model, it changes the modeling plane Z to -0.0282". When I overlay the two they appear to be exactly the same height.

I sure don't know how I did it, but it almost looks like I have changed the modeling plane for this component only.

[mtylerfl]

We can make guesses for correcting the problem you're having...or, better yet, provide your file for us to look at. I'm sure it's an easy fix.

If the file is too large to post here, use DropBox or similar free service and post the link for download.

[cac67]

Take the height below z (.0248 or .0282 depending on which one you're on) and put that in as base height, then bake it and check it again.

[Olle]

Take the height below z (.0248 or .0282 depending on which one you're on) and put that in as base height, then bake it and check it again.

I did that, and it still showed the modeling plane being out of whack. Then I used the slider in "Model position in material" to set it to "gap above material" and the modeling plane is now at zero Z. I believe that took care of it, I compared the heights with the original (which I fortunately saved) and everything appears to have the correct heights now. I ran a few tool paths, and had no error messages or other problems.

Thanks, I really appreciate it!

[Olle]

Well, I guess I spoke to soon. Did a test run, and long story short: it didn't come out right.

The problem seems to occur when I change the base height of a component. I have always been of the impression that changing base height and then baking will place the bottom of the component at zero Z (ie: Removing everything under the XY plane), but it seems like it doesn't. When I change the base height and bake, it will appear to be correct but it also changes the modeling plane. I'll see if I can get a test file together and post it.

[Olle]

On second thought: It appears like I'm not adjusting the height correctly, so let's reformulate the question...

I have everything in order now, all I really need to do is to lower one component a bit, without changing anything else. It just needs to come straight down (ie. not shrunk, scaled etc) without changing model plane, material thickness or anything else. I figure it would be a basic operation, but I just can't figure it out... Do I need to use the slice function, or is there an easier way?

[Olle]

Still struggling with this, so I resorted to the slice function: I figured that I needed to lower the model 0.030", so I generated 0.030" slices (which, by the way, also generated a layer for each slice... ), deleted the bottom slice and baked the rest of the slices into a new component. I'm sure this is a backwards way of doing it, but it seemed to do exactly what I needed to do: Lower the model without scaling or distorting it.

All I really needed to do was to lower the component and discard everything under the XY plane, so surely enough there's a quicker and easier way to do it?

[mtylerfl]

Perhaps the Replace Below gadget. Without seeing the actual file, can't say for sure. The root of your problem could have been something else. Component list order, merge settings, base heights, etc. We'll never know

[Olle]

Perhaps the Replace Below gadget. Without seeing the actual file, can't say for sure. The root of your problem could have been something else. Component list order, merge settings, base heights, etc. We'll never know

Well, I have been working in a stripped down test file and deleted everything but the component I wanted to lower, so there shouldn't be any problems like what you mention. Really, at this point I just need to know if there is an easy way to lower a component without scaling it at the same time. Just push it down, and discard everything that ends up under the XY plane.

[mtylerfl]

...Really, at this point I just need to know if there is an easy way to lower a component without scaling it at the same time. Just push it down, and discard everything that ends up under the XY plane.

The Replace Below gadget is the best tool for that (as Michael M. mentioned earlier). Your method of the slicing/baking is what we used to do before the Replace Below gadget was available. Both methods work for what you described.

[cac67]

...Really, at this point I just need to know if there is an easy way to lower a component without scaling it at the same time. Just push it down, and discard everything that ends up under the XY plane.

The Replace Below gadget is the best tool for that (as Michael M. mentioned earlier). Your method of the slicing/baking is what we used to do before the Replace Below gadget was available. Both methods work for what you described.

This is true. I gave you an alternate method once it appeared you had rejected this method but replace below is the correct tool for the job. Your resistance to this is baffling.

[Olle]

This is true. I gave you an alternate method once it appeared you had rejected this method but replace below is the correct tool for the job. Your resistance to this is baffling.

Sorry, didn't mean to offend anyone and I do appreciate all advice I can get. I'm still trying to wrap my head around on the basic functions in Aspire, so I just don't feel like I'm ready to use the gadgets yet. And quite honestly, I thought a basic operation like this would be a standard feature. It does exist when you import an object ("Discard data below zero plane"), so I figured there would be a function to correct this after you have imported as well.

[cac67]

This is true. I gave you an alternate method once it appeared you had rejected this method but replace below is the correct tool for the job. Your resistance to this is baffling.

Sorry, didn't mean to offend anyone and I do appreciate all advice I can get. I'm still trying to wrap my head around on the basic functions in Aspire, so I just don't feel like I'm ready to use the gadgets yet. And quite honestly, I thought a basic operation like this would be a standard feature. It does exist when you import an object ("Discard data below zero plane"), so I figured there would be a function to correct this after you have imported as well.

Baffled =/= offended. I doubt any of us are offended. I don't answer many questions here, mostly because the correct answer is almost always already in the thread before I ever see it. I answered in this thread only to provide an alternate method, but I use replace below also.