Cumulating negative offsets push model below zero plane

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Cumulating negative offsets push model below zero plane

Postby Chuck Keysor » Fri Jan 26, 2018 8:38 am

Hello Aspire experts....... More problems with the same model I posted a question on a couple of days ago......

Inspecting my 3D model, which now has 118 model components in 11 different levels, I noticed that the model went .266" below the "Z plane" when it should not go below zero at all!

When I had a similar problem 2 years ago, I found out from help on this forum that I had messed up by using negative base heights and negative tilt angles (as shown in "component properties"). My model was so loused up (for this and resolution problems), I had to throw it away, costing me to loose over 40 hours of work. Ever since, I have NEVER used a negative base height, or a negative "tilt" angle. So now I am fearing another messed up, unrepairable model.

Trying to isolate the source of my little negative offsets (which add up), I turned off different levels, and found that all of the negative offset came from one level. But within that one level, it seems as though 4 parts (not repeatably the same) contributed the negative offset. I spent over an hour, just trying to narrow down which parts were giving me the negative offset, and couldn't really identify which parts, as it was cumulative in small increments between several parts and the changes in negative offsets associated with each suspect component were not consistent. But it seems as though each suspect part had used a "tilt". (Again, NONE were negative, and I have avoided negative values like the plague!)

I can't have my model change heights depending upon which parts I turn on or off. But I can't figure out how to identify this, and I don't know why this has happened since I have used no negative tilts or base heights in making this model. Looking at each part's component properties shows no negative values, but I can find small negative values by using the "Scale Z Height of Model" tool to inspect each part. This is murderously tedious.

What do I do? Why do I get these tiny negative offsets on individual components, when I haven't used subtractions, negative tilts or negative base heights??????? Can I block my parts from going negative?

Help,,,,,,,,, this is driving me crazy........... :( :evil: :x :oops: especially since this happened to me before and I thought I knew how to avoid this,,,,,,,,,,, Thanks, Chuck
Attachments
Below Z plane problem 1-26-18.JPG
front view of suspect parts
Right half all parts side view forum 1-26-18.jpg
side view with negative offset of .266"
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Re: Cumulating negative offsets push model below zero plane

Postby mtylerfl » Fri Jan 26, 2018 7:50 pm

Hi Chuck,

I don't know exactly what all is going on with your model as you add more components without studying the actual file. You mentioned you had one level that you believe is causing the problem.

I can only offer a somewhat of a guess suggestion, since I can't see the whole enchilada myself. Group those components and try moving that group to another level (you may need to change the group's merge type - again, no way for me to know). Experiment with placing the group in different places in your level's list to see if a different list order makes the problem go away.
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Re: Cumulating negative offsets push model below zero plane

Postby mtylerfl » Fri Jan 26, 2018 8:31 pm

Forgot to mention...you are doing a beautiful job on that model!
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Re: Cumulating negative offsets push model below zero plane

Postby Chuck Keysor » Sat Jan 27, 2018 1:53 am

Thank you Michael. I have to go to singing group practice, so I'll be brief......

Thanks, I'll play with your suggestion later this evening.........

I posted this question on the Shopbot Forum, and one person suggested that using the "Tilt" tool can give a small negative value, even if you don't tilt at a negative angle, depending upon where the part pivoted. This makes sense, since a couple of the problem parts had been "Tilted". Some of the parts with minor negative z-low values had been "baked", which of course erases visibility of the past "tilt" settings..........

Thanks again,,,,,,,,,, Chuck
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Re: Cumulating negative offsets push model below zero plane

Postby mtylerfl » Sat Jan 27, 2018 3:21 am

I apologetically hesitate to mention this little trick to correct the issue, because it is a bit of a hack...but here goes anyway!

First, find one of the offending components that is going below the modeling plane and select it and right click to choose Show Only This. Then ...

1) Go to the Material Setup
2) Click on the "Set" Button
3) Make note of the value of the Minimum Z (which will be a negative number)
4) Now go ahead and cancel out of all that (but remember that negative number)
5) Select the offending component that is going below the plane and go into the Properties menu (dbl-click it or select the wrench icon)
6) Add a base to the component using the positive value of that negative number you remembered from the Material Setup exercise for the base height

This should raise all of that particular component to rest upon the modeling plane with no portion going negative. Repeat the entire process for any additional components until done.

Quite "hacky", so I apologize again! :D

PS - If you have a bunch of components arranged/merged as you like, you can create a new component from visible model to yield ONE component, then make that the only visible model and go through the steps above just once. It would save having to do individual components, one at a time.
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Re: Cumulating negative offsets push model below zero plane

Postby mtylerfl » Sat Jan 27, 2018 4:49 am

more descriptive for the step 2), is click on the "Set" button located in the Model Position in Material section (this opens the scale model height dialog same as the icon in the modeling tools does. Same "negative number" info, either way- - same cat, just to ways of skinning)
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Re: Cumulating negative offsets push model below zero plane

Postby Chuck Keysor » Sat Jan 27, 2018 7:33 am

Thank you Michael. Actually, when I first saw this problem, I had a minimum Z value of something like -.2" And luckily, one of the first parts I checked, had the big offset. It had been baked, so I couldn't undo anything, but I did apply a "base height" in the Component Property window, of the correct value to cancel out the negative offset.

However, with the layout of my component tree, if one part, anywhere in the component tree has a negative value, EVERY part gets pushed down by that value, plus ALL of the other negative Z component values. That makes it very hard to identify which part is causing the problem, because the "bad" part does not stick out, as every part is pulled underwater! This is not a helpful characteristic of the software, at least as I see it.....

I wish that all of the negative offsets did not add up, pulling down the entire model. And I wish that I could use a tool to tell each part, and or every part at once, to not be able to go below a Z value of zero. And, in checking again on the Shopbot forum, someone replied to me, saying that there is in fact a "Replace Below Gadget ( http://gadgets.vectric.com/V9/replacebelow.html )". I will investigate that further of course!

Also, based on my past limited modeling, I THINK I need to keep all of the parts separate, so that I can manipulate them individually. When previously I had tipped everything together, that somethings stood out more than others, requiring me to go back and re-balance parts individually. And I have to consider the viewing angles to make sure the composition looks right from as many possible viewing angles as possible. I guess that is part of why I spend so many hours on these things........... I don't mind spending lots of time, as long as I don't get derailed by things that don't work the way I want them to, or expect them to..........

Thanks again, Chuck
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Re: Cumulating negative offsets push model below zero plane

Postby mtylerfl » Sat Jan 27, 2018 3:32 pm

Hi Chuck,

Yes, the Replace Below gadget will be the next step to trim off the bottom at an appropriate thickness. I was saving that for later! There is a good video tutorial explaining how it works and what each option does... http://gadgets.vectric.com/V9/replacebelow.html (As far as I know, you cannot trim anything below the modeling plane with the gadget. You need to use the "hack method" first, then trim off the base so everything is still sitting above the plane.)

My "hack" is really somewhat clumsy, but can come in handy during the modeling process for a quick fix. You're right that a negative component can pull everything down. One has to figure out how to avoid that in the first place. I use Merge and add a base if I've tilted a component so much that one end is going negative. Sometimes a height adjustment is needed for that and other components.

It's a lot easier to make course corrections as you go, instead of hunting through a big list of components after the fact. You can do it though.
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Re: Cumulating negative offsets push model below zero plane

Postby mtylerfl » Sat Jan 27, 2018 4:04 pm

NOTE: BAKE the component after adding the base if it has a tilt or fade. Then trim it. After trimming with the Replace Below (using the same numeric value you used for the base hack), it restores that component to the original appearance you had before. But now, no portion is negative anymore!

The screenshot shows the replace below settings...
Attachments
replace_below_settings.png
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Re: Cumulating negative offsets push model below zero plane

Postby Chuck Keysor » Sat Jan 27, 2018 7:30 pm

Thanks again Michael! I'm off to a late start today, as I was up late (designing a graphic for a friend's campaign). I'll watch the video on the Replace Below gadget (as soon as I get done answering the messages I got from the post on the other forum about this problem.........)

I suppose it would be easier to check each part for negative minimum z values as I went along. But, I didn't know I was going to have this problem! When this happened to me last time (two years ago?), I had understood that my negative minZ values had occurred since I had used negative base heights, and had made negative tilts. Since I scrupulously avoided both practices this time, I was totally caught off guard when I started to look at the entire model to adjust how everything fit together........ :cry: and perhaps that lead me to over-react.

Now, as I have had comments from you, and others on the Shopbot forum, it seems as though my problem seems to come with modeling in Aspire. Since these results of going negative on the minimum Z height create modeling problems, and since it seems like a lot of added bother for people (that would be US :? ), one would hope that the good, big brains at Vectric would try to fix this. Maybe putting an "absolute value" switch on each component, accessible through the "component properties" window. Or something else...... But to leave this as is, does not seem good at all...........

Thanks again!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Chuck
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Re: Cumulating negative offsets push model below zero plane

Postby Chuck Keysor » Sat Jan 27, 2018 8:07 pm

Michael, as a sad FYI, I made a PDF copy of this thread, and then saved it in my Aspire forum folder...... I saw that I had asked this same question on 10-27-16. One person suggested "slicing" each component, deleting the bottom/negative slice, and then re-baking the remaining slices. And you recommended using the Replace Below gadget..... But then I saw my next saved post, from 10-30-16, in which I described my modeling resolution problems with the same model that had the negative minimum Z value problem. When it became clear that there was no way to fix my too low resolution problem, I threw away the entire design, and hence I never got anywhere with testing out your recommendations on the Replace Below gadget.....

So the model I am working on now, I had to start all over, and remodel each part from scratch, at a higher resolution. And so in essence, I have discovered I am back to where I was in October 2016!

But that also points out that there has been plenty of time for someone to come up with a fundamental fix for this problem of negative minimum Z values....... Will it ever happen? Are there panels where power users give input to the brains at Aspire, and say, look, fix this, it isn't right?

Thanks again, Chuck
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Re: Cumulating negative offsets push model below zero plane

Postby mtylerfl » Sat Jan 27, 2018 9:38 pm

Hi Chuck,

An excellent way to communicate ideas for additions, improvements and even frustrations is to send an email to the Vectric Team via Support (at) Vectric (dot) com

I have always found them responsive and helpful. They also will pass along software ideas to the Development Team for review.

You know, I keep thinking in the back of my mind that there is way to avoid the issue and/or that there is a simpler solution to the problem you are dealing with at the moment. Don't know if a light bulb will turn on any second now or if it's just my imagination!

One shortcut I mentioned previously is creating a new composite model from all visible components and applying my hack (plus the trim off the base). I'll have to give this some more thought to be sure I'm not missing a simpler solution.

I admit sometimes when I encounter certain problems or issues in any software, I'll find "a way" to overcome them by the seat of my pants and just move on. That gets the job done, but it can mask an underlying problem that might benefit from further investigation.

Maybe Beki and/or Todd will see this post and offer a suggestion. They both have done a lot of modeling too and might help fill in any blanks I haven't thought of (or am just spacing out on).
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Re: Cumulating negative offsets push model below zero plane

Postby Chuck Keysor » Sun Jan 28, 2018 3:32 am

Hello Michael:

a) I'll contact the Vectric Support Team per your suggestion, thanks, Chuck

b) I installed the "Replace Below" Gadget, and watched the video. Then I went to open my file to experiment with my new gadget. I noticed that there is a new version of Aspire, so I down loaded that, then proceeded on to play with the Replace Below Gadget.

But first, I moved around my cursor, just checking out the Z heights as shown at the bottom of the page, and to my utter bewilderment, I saw huge negative Z values, like -1.5inches! I selected the top component in my design, and used the "Scale Model Height" tool, and it showed the minimum Z height was -.0106, and certainly not -1.5 inches..... Then I turned the design on its side, and looked at it from the positive x direction, and very clearly, the vast majority of the part is entirely positive, making the -1.5 inch Z height value an absolute impossibility.

Any idea as to what could have gone wrong???? Was this just a coincidence that I installed the newest Aspire update/patch before my z height measurements went out of whack???? :cry:

Thanks,,,,,,,,,,,,, again, Chuck
Attachments
Now almost all negative z 1 1-27-18.jpg
Z values reading as negative
Now almost all negative z 2 1-27-18.jpg
side view shows most of model positive
Now almost all negative z 3 1-27-18.jpg
This reading I believe
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Re: Cumulating negative offsets push model below zero plane

Postby mtylerfl » Sun Jan 28, 2018 3:50 am

Hi Chuck,

Sounds like the Material setup changed. Check that to see if the model is positioned "funny". Make corrections if necessary.
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Re: Cumulating negative offsets push model below zero plane

Postby Chuck Keysor » Mon Jan 29, 2018 4:29 am

Hello Michael. Thanks, I think you were right,,,,,,,,,,, at least when I checked Material Set-up, in the material position, there was a strange setting and I had been monkeying with that. There was a value in "Gap above model", and red text saying model is thicker than material. I cleared the value, and changed the value in Set Model Height....But I didn't take notes before I changed it all. But even after making that change, I was not getting Z height readings in the lower right as I would expect..........

Historically on the Job set-up, I ALWAYS check to do Z-zero from the top of the material. And historically, whenever I use the height indicator at the bottom right of the screen, showing the mouse's coordinates, the height of the part indicated, has always seemed to be from the Zero plane to the top of the material. So with my 2" thick material, where the part is very tall, (almost 2" thick), Historically, I BELIEVE it would have shown the Z height as almost 2".

But NOW, if I check on Job set up, to use the top of the material as the z-zero (which historically, I almost always did), I get readings (for example with my 2" thick material) of z = - 1.5, where I would have historically expected it to read +.5

To get the Z height readings that I would have historically expected in the lower right, I have to check on Job Set Up, to use the machine bed as the Z Zero position. Then it reads the way I would have been used to,,,,,,,,,,,, but 99.9% of the time I have used z zero on the material surface............... Either the software patch that I just made yesterday did this or I have just been confused all along..........

Well, thank you for your tip,,,,,,,,,,,,, if you were right, thanks, and if instead, I have just been confused all along, you got me to look in the right place....

Sorry to keep dragging this out, and being slow to respond............ I keep getting dragged off on other things........... Thanks, Chuck
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