I received an email a couple days ago from a student at the University of Michigan that goes like this:
I just discovered your blog – very nice.
I was impressed by your parametric Mission Table. Especially how you handled the parametric mortise and tenon joints. I’ve been able to make parametric tenons no problem – but I don’t know how to make the mortises auto-update when the tenon changes. Does your model do that? If so – any way you can share it – or a part of it – so I can see how you accomplished that?
Again, thanks for your blog.
Sincerely, Mark Meier
The short answer was no.
Generally mortise and tenon joints are sized to the available tooling, and are based on the particulars of the design at hand. In my case, I use a Powermatic 719A Mortiser (shown to the right) and have ¼”, ⅜”, ½”, ⅝” and ¾” hollow chisels. While designing a piece, I pick one of the chisel sizes based on the strength (or other factors) needed for the furniture item in question. A ¾” thick stretcher on an end table usually gets a ¼” tenon, and the leg gets a ¼” mortise to match.
But in the case of work being sent to a CNC router (or template routing by hand), there is a bit more flexibility as to joint size. You may want to tweak a tenon size up a bit when switching from white oak to pine for instance.
I played around for quite a few hours trying to get iLogic to do what I wanted it to do without writing Visual Basic code or delving into the API to no avail…
I was able to hack a rule that would take care of the top edge detail, but that was only by changing the parameter from a string parameter named Top_Detail with the values Flat and Bullnose to a Boolean Parameter named Bullnose_Top which is, of course, true or false. I then needed to create the actual feature in order for things to work, which sucks, but it is what it is.
Now when Melamine is chosen as a side material, the Lumber_Species and Side_Ply_Type parameters are unavailable as desired, the Side_Thickness parameter defaults to ⅝” and also has the ½” value available —-again, as desired. Skipping over the finish and bottom related rules which have not been written yet, we get to the new Bullnose_Top parameter controlled by this rule… Continue reading →
I will start by writing iLogic Rules that I will reuse on a manufacturer-specific basis as each SmartPart is intrinsically linked to manufacturing capabilities…
…because the average drawer box component manufacturer may offer a thousand or more possible configurations for the drawers (and usually doors) they offer, the first place to start would be developing a robust set of rules for the top-level options.
These top level rules will act as a filter for the lower level rules –turning off those that are no longer applicable e.g. a drawer is configured to be constructed of Melamine at the top level of the configuration process therefore Lumber Species in no longer a viable option, nor is the finish (and numerous others) —and vice versa.
I will be testing out an iLogic configurator as I go, so there will be a bit of tutorial action going on by default as I stumble my way through something new ……I’ll do plenty of stupid things, and report them to you so that you can laugh at me avoid them yourselves Continue reading →
I had a long conversation with a savvy woodworker in Maryland yesterday about whether Autodesk Inventor is ready for ‘Prime Time’ as far as the wood trades go.
The short, general answer is “it depends”…. but in his case…. “no”.
His shop will be heavily reliant on output to CNC machinery, and Inventor is heavily reliant on third party developers for all of its CNC output . What I have seen of this third-party software so-far is underachieving at best, and at a very high price.
Anecdotal Drivel; for What it’s Worth…
A few months ago I watched a video presentation from one of the big name CAM Add-on developers that showed how to take output from Inventor —– a pattern of holes in a solid body—- and recreate that same hole pattern in their software! This is like composing a letter in MS Word, then recomposing the letter in another, lesser quality word processor just to print. I actually thought the video was a joke for awhile, and that they were going to spring out some software gee-wizardry at any moment. But, no. It was lame by design. They were totally serious.
Another big name CAM add-on I am familiar with from my yacht making days forced the CNC operator to convert Inventor parts to ACIS solids, explode them, then manually set router paths and drill procedures to the lines and other geometry pulled from the exploded part. On the design side, we designers needed to create grain direction and ‘money side’ indicators that were cut into the Inventor parts to serve as visual clues for the CNC programmers. The whole process was just a tad quicker than beating the parts into shape with a dull rock, and much less fun.
Last night I captured a bunch of images while creating the half-blind dovetailed drawer box so that I could give a quick overview of the modeling process…
I’m not going to go into anywhere near a tutorial detail level, but would be happy to create one at a later date if there is strong enough interest.
Everything in this model is centered on the YZ and XZ origin planes and rests on the XY origin plane. Some of the construction geometry serves no other purpose than as a visual aid in support of design intent.
The lines to the right of the dovetail profile below are merely to get a aesthetic clue as to the spacing of the tails…
…the single tail that was modeled is an extrusion with the Taper setting set to a parameter. This causes an angled hollow at the outside face of the tail that needs to be flushed-up with the outside face of the box. Continue reading →
In the image to the right you can see one of the incredibly complex iLogic iDrawer SmartParts line constrained in an assembly to the as of yet skeletal iCabinet.
I had hoped to get this out yesterday, but the website maintenance wound up taking a dozen hours or-so, and it wound up being one in the AM before the iDrawer was completed to the stage I needed it to be to insert into the assembly shown.
Now I need to go back and forth between the cabinet, drawer, and the iLogic rules which will mostly reside in the top, assembly level of the model. I also need to write the set of rules that control all of the options for the drawer, which, depending on the manufacturer, could be very extensive.
I may need to use the confidity configurator on this one, but time will tell. In the image below you can see the user parameters from the model , which need to be connected via rules to the iLogic parameters shown in the May 11Th post…