Are you mistaking checking the remaining values with over constraint. Take note the angry orange is a dead end and after checking the value, the dialogue box is cancelled to go back to the green
This works well for drawing out an existing design. Prototyping is more on the fly, things can change drastically from iteration to iteration
I didn't realise a new version was out, thanks for the tip
DecibeL
You may not see any significance in my findings with things like implications for spanning over hairline aire gaps and as such it probably doesn't affect how you model. I tend to aim for a showroom+ fit and finish and try to account for skins such as the 60gsm that I use on fine stuff as well as for things like powder coating on custom alloy parts. Think hypervirgo 😉
If you define a set of unconnected lines with small gaps between the end points you won't be able to create a solid model which requires the lines to form a closed loop without gaps (but you will be able to create shells with gaps and a lot of confusion about why things like fillets don't work as intended). You will also have to supply a bunch of extra dimensions to fully constrain the unconnected lines compared to a closed loop which is part of what was baffling me above. If you want to create valid solid models the gaps must be removed by making the relevant pairs of end points coincident which is the first constraint in the list. If you want to avoid the hassle of this then define a single polyline rather than a lot of individual lines. FreeCAD is a tool that can do what you want but you will first need to learn how to use it as intended. I am not familiar with FreeCAD and don't know if there is a good FreeCAD tutorial. A reasonable general introduction to constraint based modelling is likely provide most of what needs to be understood though.
Every few years I have a quick play with FreeCAD to see how it is coming along and this time it worked fine in creating your sketch and a drawing of it with dimensions formatted to 6 SF in the TechDraw module. It still doesn't have an Assembler but this is only really an issue for larger models. A model for the parts of a speaker should be fine to assemble manually. Although I haven't tested it fully it looks as if FreeCAD might now have become a useful tool for some projects.
Andy, the issue isn't drawing the shape that I did. As you found out, it's easily done. It is a very simple shape. For my particular model I need the parts that go on that to line up, but they don't and seems can't line up exactly and the following part gets worse and the next one worse. If there are a number of panels that need to go around a bend in smaller sections, then by the time you get around the bend, it no longer follows due to panels being straight and every fraction of a mm discrepancy displayed by looking up the last to find the location of the next. Simulations of a single panel needs to be done using separate sketches as the next connected one and the same sketch shows up hollow
I haven't been able to get around that bend by simulating individual panels. They won't line up to the end as FreeCAD rounds off to the number of decimal places displayed and the number shown in both the dialogue input field and sketch label do not always show the complete number and round off to different places
I haven't been able to get around that bend by simulating individual panels. They won't line up to the end as FreeCAD rounds off to the number of decimal places displayed and the number shown in both the dialogue input field and sketch label do not always show the complete number and round off to different places
Carlson Hulls is a program designed for simulating a boat (box) using board material. It can do just about any bend and angle and line up edges perfectly. But it creates a defined number of lines first and only one edge of the ends. A different way but much more effective for very complex boxes and does the part of nesting onto a defined board size at the push of a button. You can select the parts you want to loft onto the board and just move them around until just right for manual cutting by lining up straight bits and going for max usage by fitting as much as possible for CNC. You can even set the board as a large format paper and order printed templates for manual cutting from most print place
Things we come across about software behaviour is not a peeing contest either. It's meant to help someone who might be scratching their heads over some lil mystifying issue. Blanket statements does not make lil difficulties go away. Raising what I run into might help someone correct for a failed print while blanket statements would be of no use to the one seeking a particular solution. The fact that I have to say this out shows how pointless brushoffs are
Things we come across about software behaviour is not a peeing contest either. It's meant to help someone who might be scratching their heads over some lil mystifying issue. Blanket statements does not make lil difficulties go away. Raising what I run into might help someone correct for a failed print while blanket statements would be of no use to the one seeking a particular solution. The fact that I have to say this out shows how pointless brushoffs are
I do not understand what you are trying to do and I cannot make out what the picture in #3 is supposed to be but if you can explain in words or link to a picture of what you want to model it is likely people here will know how to tackle it. Given you are referring to lofting and hull design software I am guessing you want to model something like a bendy port/horn but involving straight sections in some way. But I'd rather not guess.
Exactly the situation
Maybe the best way to describe is very tiny errors that creep a set of consecutive objects away from the intended line. These errors stem from using the rounded off numbers that FreeCAD displays. Maybe if the program offered only two decimal places as an example and showed a warning when this was rounded, then work can be steered away from the discrepancies
Again, it's the rounding off that I am trying to highlight as a caution. Nothing more
So we want to model a horn. Where do the straight sections come in? Can you please point at a picture that includes straight section of roughly the right kind?
Andy, not just a horn but a sim of the whole cab including fit and finish. As long as the next sketch relies on the locations from the one prior, round off the decimal places and not knowing how much is being rounded off will never allow for an exact fit. Fine for a drawing that is already completely sorted but no good for on the fly prototyping. I wouldn't take the time to recreate the attempt to draw a series of back panels where I discovered this issue
Starting from a block and carving away seems to avoid this issue as all internal cutaways can be done within one sketch and this eliminates the creep from having to call up already rounded off numbers
Starting from a block and carving away seems to avoid this issue as all internal cutaways can be done within one sketch and this eliminates the creep from having to call up already rounded off numbers
No problems. If you are happy with whatever you are doing I will use something else to check out FreeCAD.
Maybe try to draw a leaning box simulation using individual panels. Zooming in to the limits will show that the back edge can't line up
Didn't imply any rudeness. FreeCAD is very unstable on my system and takes forever to open, save and such and keeps opening up the sketch I didn't double-click on if I have more than one project open
I spent a couple of hours yesterday playing around with various ways of modelling a speaker in FreeCAD and although a noticeable improvement on what I found a few years ago it still has some significant issues. The most serious I came across in my brief dabble relates to the identity of objects after OpenCascade has performed an operation (FreeCAD is effectively a wrapper around OpenCascade which does the heavy lifting). OpenCascade doesn't guarantee to preserve object identity but simply returns a list of geometric objects after each operation. Rather than then working out what's what correctly (a significant amount of effort to get right because identity isn't as straightforward as it might seem) FreeCAD appears to perform some form of guess that is usally right but occasionally wrong plus, what's worse, getting the user to provide extra unecessary information to improve the guess. It also converted some of my speaker dimensions in a spreadsheet to a value when creating a part but then seems to have discarded the information that the values came from the spreadsheet. I updated the values in the spreadsheet (which is the whole point of using parameters) and the values for the part remained unchanged. The parameters appear to update in some places but are only read once and not preserved as parameters in others. I stopped at this point. FreeCAD is not reliable for developing solid model but for me it may be useful for browsing and perhaps fiddling at bit with models largely created elsewhere.
Perhaps I should add that solid models were successfully created (OpenCascade is reliable) but it required more effort than it should (fair enough for free software which isn't going to be polished) and it required continual checking to find out whether what should have happened did (fair enough for some but not others). I expect that if a user invests time finding out what works and what doesn't, how to get round the problems and updates things when new versions come out FreeCAD is a free and useable CAD package. For me it is currently too much work compared to developing models with scripts but for those that are not comforable with scripting it is an option to consider. Good to see it progressing and I will likely keep it installed on my desktop for the odd dabble rather than removing it as I have done in the past.
Perhaps I should add that solid models were successfully created (OpenCascade is reliable) but it required more effort than it should (fair enough for free software which isn't going to be polished) and it required continual checking to find out whether what should have happened did (fair enough for some but not others). I expect that if a user invests time finding out what works and what doesn't, how to get round the problems and updates things when new versions come out FreeCAD is a free and useable CAD package. For me it is currently too much work compared to developing models with scripts but for those that are not comforable with scripting it is an option to consider. Good to see it progressing and I will likely keep it installed on my desktop for the odd dabble rather than removing it as I have done in the past.
FreeCAD has its issues, but most can be worked around to get some very complex models. It's actually quite good at speaker cab models via carving out from a block and using the pad and pocket tools on facets to keep everything exact instead of using sketches to pull these. My Cub Sandwich threads are a good example of how intense and exacting some cab sims can be in FreeCAD
Member
Joined 2003
Under General preferences - default unit system, change the number of decimals there.
How does this prevent FreeCAD from displaying a rounded off number to those new places? A deliberately obtuse way to not acknowledge a real issue
Member
Joined 2003
Maximum of 16 decimal places are supported, if that's not enough for you I can't help you. Perhaps the FreeCAD forum is a better place to continue the discusson.
https://forum.freecad.org/
https://forum.freecad.org/
And FreeCAD will still display a number after rounding it off. The next part that needs to start at location will never fit perfectly. This is not something that I require assistance with. But rather pointing out a caution to other noobs like me. I can’t believe that you can accept a rounded off number. Do you know what rounding of is and its implications for fit and finish?
FreeCAD is what it is, I am sticking with it only until I can migrate to Solidworks. My findings are relevant here. The FreeCAD team must be well aware of this already
I think this nails it. Some people who are not noobs when it comes to CAD suspect the problem is with the user and not the tool. However, unless you tell us what you are trying to do rather than alluding to how it can only be a suspicion due to a lack of information. Of course if you want to work things out yourself without help that is perfectly fine and understandable but blaming the tool is less so and likely draw fire and/or attempts to help with how to use the tool which you don't want.
If you believe there is a problem then the right thing to do to help open source software develop is to post a bug report which will require you to provide enough information for a third party to reproduce the bug. I suspect you are not going to like the response but it is a better thing to do than post here. In the case of the two issues I mentioned above FreeCAD developers have written extensively on the problems and the ways they are addressing them. I don't agree with their (incomplete) solutions and so like your problem having first looked to help I have recognised it is not wanted. This post is to let noobs know there is disagreement about whether there is an issue with FreeCAD/OpenCascade and the precision with which it performs calculations.
Staying with that question. Please see the pic in post 12. As already mentioned, that's a left panel and the base panel. Now create the back panel. Let's say 32mm board material. FreeCAD default is to two decimal places, so set that. This exact detail is already given, but let's go through it again
Ok, create the back panel sketch. It would look like a leaning board with angle cut top and bottom. Now create the lil horizontal panel and the lower back panel. Zoom in all the way and check the edges
I think this is the third time I am listing how to reproduce the incident. What other details can there be?
Ok, create the back panel sketch. It would look like a leaning board with angle cut top and bottom. Now create the lil horizontal panel and the lower back panel. Zoom in all the way and check the edges
I think this is the third time I am listing how to reproduce the incident. What other details can there be?