I dont understand direct Modeling!

Hi just wanted to ask what is your Workflow and mindset for direkt Modeling?
I mean i dont understand why direct modeling is faster or More flexible than parametric modeling.
If i want to Build something like a Box for a cabinet at first i just know i want it to be Open at the top, 4 Walls and a baseplatte. Next Stepp would be to Measure the cabinet for height width and depth and change my Parameter. Next i Go to the Hardware Store get Some Wood change the thickness on my Parameter and im done. With direkt Modeling i have to know this all at the beginning or it will be a mes to change the thickness of 5 (for More komplex Models Maybe 20/50 Parts etc). Or even at designing things like a mesh or repeating pattern like a ventilation grill if i want to look if more or less holes or more or less diameter looks better its just 2 clicks in parametric and in direkt Modeling its a lot of selecting and not very intuitive. I often discovered that doing changes Later is much More complicated in direkt Modeling than parametric and doing quick changes is claimed to be the key Feature of direkt Modeling. So were is my mistake ? I realy want to understand the mindset of direkt modeling cause i love the look and feel and Mobilty of shapr3d.

Hello Quigonlong,

In this list so many specialists and I not one…but I give you the link of a brilliant demonstration about what is direct modeling compare to parametric. Hope this help you !

Webinar from Shapr3d

If I remember correctly the wonderful teacher start to explain parametric then, around 20 minutes he shows the direct modeling technic.

And also :
https://youtu.be/6j9OWgo68HM

Regards,
Didier from France

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Oh boy, what a statement.

Your perception is only yours, which modeler you choose to have things done is your business.

I am using parametric 3D professional CAD programs on daily basis since last century, as I am older than internet :smiley: (watched cartoons on black and white tv as kid).

Pain from parametric modeling can be shown by questions like:
How many times you’ve got error on model update after modification of base sketch?
How long it took you to find which constrain missed parameters?
How many other modeling features got errors because other error?
How long you wait for program to start, refresh, etc…?
How many times you’ve been pushed to spend money for one way upgrades because you use older program version than your client?
How many times you need extra paid translator to import things between expensive parametric programs?

I agree that with parameters you have more control over much more steps in few clicks (if you modeled thing correctly).

Since 3 years as I have Shapr3D I can start IPad and modeling my ideas within 1 minute.

Compare your CAD here. Start computer 3min start program 5 min select correct template click here there… oops not there… etc updates, typing values…

… while I already finished modeling and shared step file with client.

Shapr3D is always there where I need it.
If I am asked for review I receive step files, and within few minutes I have feedback based on screenshots and my markups.

That’s my point of view and use case scenarios. I think with Shapr3D I am at least 10x faster, saving a lot of time , and can do more things now without waiting for parametric CAD to open.

In professional environment where we design module with 80+ engineers working in concurrent engineering methodology, Shapr3D cannot be used for real mechanical design, however I used it on few meetings to quickly explain design intentions. You can’t do it in normal CAD if 15 min meeting left.

I hope my case will help you to understand why some people prefers freedom of direct modeling.



All the best
LePapa

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LePapa, I’m confused about how to direct model. I create a sketch, extrude it, all good. But change the sketch; not just update a dimension, but significantly change it. The changes are not reflected in the body. What do I do? I’m a parametric guy and am lost. Thanks for your time

Once you create the body, the sketch is no longer associated with the body. You now work on the body directly. This is direct modeling.

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Starting with your …
“… I’m a parametric guy and am lost. “
… so you prefer to modify model geometry and topology via invisible cross sections of lines and sketches of who knows how was created… and first of all you need is parameters table to click type and change … you need to decide if cylinder is based on extruded circle or rotated rectangle or triangles forming rectangle … (we don’t)… I understand … you need it it’s your workflow, fact is fact (we don’t). You probably have direct modelling tools in your parametric CAD but you are need conservative traditional workflow … that’s all fine. In fact project I do work on right now also need it (3D complex surfacing with parametric splines etc…)
Sharp3D was used for beautiful rendering .

… but take you time play around and believe me you shall find joy and pleasure of direct modelling …

If you want to discuss any design example and compare parametric way of working to the direct modelling drag and pull what you click is what you modify … shoot an example … let’s have fun.
But you need to wait until I get Shapr3D licence back as my current project is indeed parametric to the max and too detailed in amount of surfaces, fasteners etc so I am out of Sharp3D since 4weeks unfortunately using professional rendering software for my project.

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Thanks for your responses McD and LePapa. I’m old and my brain is wired for parametrics, so it’s hard to figure out. Regardless of direct vs parametrics, typically you have a root body that many other bodies are associated to. At least in my experience, there are many situations where the root body may need to change for whatever reason. In many cases the sketch or body, and associated bodies, will need to be repaired. But I can do this very quickly in parametrics. I can’t get a damn thing to happen in direct. But everybody raves about how fast direct is. So is there a way to get a body to update with a modified sketch, or do you just create a new body and delete the old one? By deleting the old one, does it affect the associated bodies? Thanks!

Throw out the Engineer and bring in the Artist. :blush:

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@amillson, provide an example of an item you’d like to complete or change after an initial sketch is created. I’ll give it a go and show you some of the benefits of direct modeling. For my workflow, I make an initial sketch kept as simple as feasible, extrude to my liking and from there modify or alter the body. I would then either delete the sketch or simply hide it for future reference if needed later on.

And, if I may say to @LePapa, yes Shapr3D can be used for real mechanical design. I’ll share an item I designed in a new post, soon.

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Hi TigerMike, an example would be the very first part that I attempted to model in Shapr3D, a revolved handle for an espresso portafilter. Coming from Pro-E/Solidworks/Fusion360 I was very excited to find that Shapr3D worked on my Mac (I plan to buy an iPad Pro and pen in the near future). Once I created the sketch I revolved it around the axis. Then, looking at it, I immediately wanted to change the profile, which I did. And nothing happened. Then, searching this forum, I made the horrible discovery that Shapr3D is direct, not parametric. I’m okay with that and up to learning new things. I understand your advice to start with simple geometry, but it kind of misses the point. Don’t you ever want to make a quick change/modification/adjustment that propagates with zero time and effort, other than possibly a few surgical repairs if the geometry is complex? Maybe that is not how direct works. If my sketch is now useless, does that mean that I should just delete the revolved body and start from scratch with a new updated sketch? Seems very inefficient. Thanks

Hi Andrew,
Yes, you may have to trash or hide the body if it cannot be salvaged. Upload a pic of your sketch and show me what you want to change on that sketch that you’ll like to see changed automatically on the revolved body. Are you making aesthetic changes or exact dimensional changes? I found this pic on Google Images and there are a variety of handles. Is your handle similar to any of these?

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One thing that has bit a few people in the behind in direct modeling: Sometimes you can’t go back/ undo operations on a body you have put much time into. You must toss it and start again.

For this I have learned to create copies of the body at checkpoints (if you will) and hide them as a backup to revert to if I change my mind later or want to make a “fork” in the design.

The undo/ back button does not always work after logging out and back in.

IIRC Parametric modeling has limitations on the order of and or how far you can backtrack sometimes.

Once you get a pen in your hands, you will experience a speed boost in fleshing out designs. Game changer.

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What OregonNerd says is wisdom. As you learn, you’ll become savvy on when to save a backup file, or realize you’re going diverge into another revision. It has become second nature to me to save versions as I go along. I also save a comment in the name to help me know what version it was. i.e.: Hammer Design - large claw with extractor.

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Thanks all for your replies. TigerMike your screenshot is exactly what I am designing, and the changes are both aesthetic and dimensional. I am trying to get into the direct mindset, but all the Youtube videos are created by direct fluent folks, so they tend forget that their muscle memory is not yet natural for newbies. Anyone know of a good “direct for dummies” video?

I suggest our youtube channel, there are short tutorial videos, but also longer design videos too. The longer ones could be especially useful for you, even if the end design is different, doing it with the video can help you a lot to learn how Direct modelling works.

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Yes, but if you want to change a dimension you’re now working on the body directly and can’t “replay” The things you did (chamfers, etc) to keep things consistent. This is my lack of experience with modelling, I’m sure, but I can’t seem to figure out how to make semi-complicated mechanical models which need to be constrained in a way that I can make fundamental changes (hole size/location) and still retain the work done to date.

This is possibly one of the big “missing links” in my journey too using Shapr3D. It never occurred to me to “copy and hide” bodies as a snapshot mechanism, thank you!

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