3d model gaps and spikes

[Chuck Keysor]

Hello Shopbot Friends:

The first image shows another 3D model of a Victorian house decoration that I have recreated from an old photo. (Because it is kind of weird, I am distancing myself from the design! ) The previously posted example was made of many single rail extrusions, which created one big part. But in this case, I have lots of smaller parts, modeled using multiple Aspire tools. Each of these parts is then assembled in the parts modeling tree.

Question 1: The gaps shown in the second image are about .06" wide. Can I just ignore these? Or must I fill them in?

The gaps are very narrow, BUT I am using a .0625" tapered ball nose end mill for the 3d finishing path.

Just because it bothered me to have gaps, I did play with the Aspire "smoothing" and "deposit" sculpting tools. But no matter what strengths and brush widths I used, I was noticeably messing up the appearance of my part by the time I had actually filled my gaps.

Question 2: There are razor thin spikes where some of the subcomponents must be over-lapping. These are so thin, I couldn't really measure them. Should I simply ignore these spikes?

These are so thin, I feel very safe in ignoring them. But it seemed like sloppy practice to leave them, so I did experiment as above. And I found that I may have damaged the appearance of this part, so I don't want to do that.

Thank you, Chuck

[bleeth]

The sculpt tools do take a bunch of work to get used to. Are you sure the gaps are that large? If you created it right as far as the controlling vectors go they should be smaller. Often it is just a matter of model and/or screen resolution and it will cut fine. For the "spikes" a smoothing pass or 3 over the whole model usually gets rid of them.
There are also some toolpath creation tricks that work for me. One of them is to take my model outline and offset it in a tiny amount and use the offset vector as my tooling limit.

[jamesb]

Chuck,

You might want to try higher model resolution to mitigate some of these issues.

Regarding gaps - its good practice to overlap vectors/components a little to avoid gaps unless you intend them - these may or may not show up clearly in the cut part as is but the preview should show you if they need "fixing" or not.

Regarding spikes - you should not ignore them and smoothing may help but can also affect detail. Normally the best way to deal with these is to set the Components combine mode to Merge rather than Add or Subtract - that way where they overlap they will just blend together. Depending on how they combine with other components in the part you may need to group some of them or adjust heights after this to ensure they stack up correctly and don't disappear or get lost under other shapes.

Thanks,
James

[Chuck Keysor]

Thank you Dave and James for your replies. You moved me to consider that I should not simply ignore the gaps and spikes. So, I went back to an earlier saved copy, prior to having baked so many subassemblies together. I found to my mystery, that the base plate component was set to add and not merge, which is what had created the spikes. So I quickly eliminated the spikes by changing to merge. Then I enlarged the base plate in the areas where the gaps existed, and then eliminated those because of the now enabled merge mode.

I feel a bit dumb in retrospect. I had created and saved so many versions of this model, and worked on it some here, and then there, that I didn't keep track of what I had done, and as a result asking a dumb question.

If I were now somebody reading my original post, knowing what I know now, I would have said, "Gee Chuck, I think you have to go back and look at your model to make sure you have all of your components in the merge mode, and that you have a little over-lap of those parts that now have a gap between them!"

Thanks again, Chuck

[Brady Watson]

Don't feel dumb, Chuck. These are honest mistakes and all part of the learning curve. I'm glad to see you are actually using the software for building assemblies. Many invest in software and do nothing more than cut clip art as purchased. Hopefully you are having fun in all this!

-B

[jamesb]

As Brady said, not dumb at all. Just part of the process. Glad it helped fix the issues.
Cheers,
James

[Chuck Keysor]

James, thanks again, as your advice was "spot on"!

Brady, thanks again for your continued encouragement. As to the question of modeling, I do find it interesting, but amazingly time consuming. It has never been my intention to purchase 3d models. I always try to find some area where I get more involved, and creating my own 3D models is my objective with the Shopbot. That is why I also bought Rhino, so that I would be able to build more complex models.

I bought a set of very good Rhino training videos from Infinite Skills, and watched the first full CD, and modeled a fairly intricate porch railing with Rhino (and built using my Shopbot). But that was in the first quarter of 2013. When I started the current project to recreate the 4 missing Victorian house decorations in February of this year, I started using Rhino, and realized that I had forgotten how to use it! I was dumbfounded, and instead of trying to brush up on Rhino, I fell back on using Aspire, which is easier to get to a functional level of 3D modeling skills.

What was frustrating with the Aspire 3d modeling, was what I will call a lack of associated history files for each component. To model the acanthus branches, there may be 15 different single rail sweeps. Some single rail sweeps may have as many as 10 different cross sections. While working on any one single rail part, you can go back and move cross sections, change them re-sweep, until that part looks good. But then you add some other parts to the assembly, and then an earlier part starts to look wrong, so go back to fix the earlier single rail swept part, and you have to start all over. You have to start all over because the sizes of cross sections and their locations in the original model are all gone. It sure would be good if each of these single rail swept parts carried with them all of this original construction history, so it would be easier to go back and edit parts instead of having to start all over when some tweaking is required.

It is quite pleasing to be able to go and rotate a model in 3D space, and notice that while the model matched the historic photo that was taken from one view, that when viewed from a different angle, the 3D model looks wrong. And that it is possible to change the model to look good from a more conventional viewing angle, while NOT messing up how it looks from the angle in the historic photograph. Not sure if that is clear, but that is part of what got me doing LOTS of iterations, and then getting frustrated with the models I had made not having any associated history.

And I also then wondered if the process would have gone better in Rhino.

Thanks again Brady for your assistance! Chuck

[Brady Watson]

No problem, Chuck.

No, Aspire is the right tool for the job. Rhino is lacking when it comes to 3D relief creation and manipulation. You can fo course, import and export between the programs to combine different functionality. I find there are times where I need a Z modulation vector to control the shape as it rises and falls during a rail sweep, so I might do that in Rhino, then import it into Aspire to continue my work. It all boils down to what you are doing. Rhino is great for 3D visualization and viewing assemblies, but for reliefs...Aspire has it beat by a mile.

Yes all of this work is time consuming. However, if you treat it like learning how to play an instrument, and realize it takes time for parts of your brain you've never used before to catch up....You will be rewarded down the line. Yes it is work - which is why not that many go very far - but if you are dedicated & work through the frustration(!) - You will be rewarded. It isn't 'just you' - you are right on track & this is all part of the learning curve my friend.

What you are up against has more to do with finding your particular way of working in order to stay organized during construction. It is easy to get way out in left field when you are "in" the computer - and then need to back track. I throw all individual component vectors on their own layer (both vectors and reliefs) so that I can easily parse out the stuff I want to keep and the stuff I want to work on exclusively. I don't bake ANYTHING until I know for sure I am ready to do that. Plus, the way I work, if I HAD to bake something to continue, I'd have a copy of the component before I 'cooked it' waiting in the wings. Yeah...convoluted - but reality nonetheless.

I am not going to speak for the Vectric developers, but I will say that you'd probably need a MASSIVE 'scratch file' to be able to selectively undo all of those commands for each historical move for each component. Every move you might want to undo must be saved somewhere & this may be larger than some computers are capable of doing - or may cause performance problems for people. So, yes...this would be GREAT! - but, the reality is, it is tough to implement.

Also, it is important to step back from the computer once in a while (I am not saying this to be terse) - in order to get some perspective. Aesthetic is sometimes VERY difficult to pull off especially when working with digital equipment. I've had the unique experience of 'getting' that the only things that are 'perfect' are those things which are 'imperfect'. That is to say, imperfections, dents, cracks and other non-symmetrical details on architectural ornament are the exact thing that make the entire aesthetic. This is why if you walk into Hobby Lobby and see all the cheap imports - they are devoid of real character. They are too smooth, too 'perfect' - and lack 'music' running through them. Only through laser scanning old authentic pieces & then working with them in software to make derivative works did I realize just how much these little imperfections add to the overall piece.

So...sometimes you have to step back...or ask someone else where the piece 'needs' something in order to make it appear genuine or 'correct'. But, my point is there comes a time when you have to stop modelling because no matter what you do, it will not have the exact same 'flavor' as something that has been hammered out by hand and the elements. This is where finishing really cures many of the 'sins' of modelling digitally.

Does that make sense?

-B

[bleeth]

Chuck:

90% of my design work is 2D furniture parts. Every time I get into a 3-D project I feel like I am learning it all over again. Glad James popped in with the "merge" mention. One thing that can help you to go back to a certain point more easily is to make heavy use of the layers tools. Not sure about Aspire but AC has the ability to have multiple relief layers in one model that can be manipulated independently.
Very Helpful.

[Chuck Keysor]

Hello Brady. Thank you for your added advice. Concerning the use of Aspire vs. Rhino, I had some foggy fantasy that Rhino could model anything, so I am glad to have that notion eliminated! Knowing Aspire is the best tool for relief work will help me to move forward.

Last year, as my learning exercise in Rhino, I designed and built a railing for my house. I used my Shopbot for cutting the 15 foot long rails (more as a learning exercise than being practical). And I cut all the detailed, two sided gothic arches on my Bot. An image of the Rhino model is attached. The second image shows up close of the installed. I was going to model a Gothic Rose to inset into the empty square recesses that are at the tops of the posts, but I never got back to it, as I had planned (mistakenly) to do that in Rhino. But now I will proceed to make these added elements in Aspire. Again, your direction is helpful even in this regard.

I have been keeping my Aspire "model" tree for my recent Victorian appliques very organized, saving "grouped, unbaked" sets of parts, and starting each new day's work with a new file name. But management of the 2D layers is somewhat buggy, in that I do find that for unknown reasons, parts seem to get relocated to wrong layers (though they are easy to move back with the move/copy part to layer/new layer command).

Your comments about having great complications in the software to accommodate what I call "history" is understandable. But even when I made that complaint, I was half wondering if Aspire did already provide a "history" file, and I had simply missed how to access it. But now, I won't wonder, and can have less consternation knowing it isn't there, and probably won't be.

As to the aesthetic matter, I am pretty much stuck by myself. The people I know look at whatever I make and just say, "cool", which isn't very helpful. Everything can't be "cool". And in the case of the part that last week I posted about crashing my bit into my table top,,,,, I had looked at that so many times on the screen from so many angles, and it looked OK. But then when I cut it out of blue foam, and could look at the real part, I thought, gee, this needs a little more relief! But no way am I going back to modify all of those model cross-sections and revise my model! I hope/suppose that with time, comparing enough computer models with the actual parts will help me to see the models more objectively.

Thank you again for your thoughtful advice, Chuck!