Is there a theory for complex modelling?

javl0p_2 · March 24

I've been doing parametric modelling for quite a few years now, but I recently started scraping onto the surface of complex modelling.

What I mean for complex modelling is the one requiring a lot of surface modelling and advanced operations in order to model shapes that we commonly encounter in Industrial Design. You can think of cars, hair driers, earbuds or even modern furniture.

When dealing with simpler shapes, there are methods such as braking the shape into basic primitive forms or imagining the manufacturing process and modelling each step of it (that one I prefer, since it takes into account manufacturability).

However, I found myself struggling with surfaces that I am not able to break into simpler operations. Sometimes I am not even able to figure out the key curves that serve as a scaffold.

I was wondering if there is a methodology for complex surfaces. Is it just experience that I need or is there a theory I should learn first?

I would appreciate any references that you could share.

Thanks!

nick_papageorge073 · March 27

I have some experience with this. I worked for 15 years on mass produced children's products: infant carseats, strollers, highchairs, swings to rock them to sleep, etc. Everything was injection molded. Everything was to look fancy and organic.

It's not easy to model this way. It takes a whole different approach. For "block type engineering" you can model with simple sketches and extrudes. Then add rounds to smooth things out. When surface modeling, it's the opposite. You need to have the final shape very well thought out. The rounded portions are actually modeled and there are curves defining them. Rounded portions are not created with the "fillet" tool.

I was new to this in about 2004, and I had an Industrial Designer teach me how to model it, and teach me how to think through it. What helped me early on was making a clay model of the shape intended. Then tracing with a pencil to make a shallow groove on the model everywhere there needed to be a curve in the CAD system (I was using ProE, now called Creo, at the time). Then coming up with a game plan to make those curves in CAD, and then making the surfaces. Generally modeling like this is called boundary blends. Each boundary blend surface needs 4 curves to define its perimeter. (I forget if OS calls it something else, as I've not had to do this since switching to OS).

As I gained some experience, I was able to do the sketches on paper and skip the clay model. On those paper sketches I'd draw all the curves that defined the surfaces, listed the game plan, the order to make the curves in CAD, what planes I needed, etc.

These surfaces also have to be able to "reflect light" smoothly. When you look at a car, and move your eyes all across its panels, it's beautiful. The light reflects evenly in the sun. There are no "hot spots" of light. This is one of the goals of surface modeling. There are "comb" tools in all the CAD programs to see how they reflect light.

Disclaimer, this info is 15 years old. IDK if there are newer tools now to do it simpler. My last 5 years I was doing simpler "block style" modeling only.

Another disclaimer, I doubt this info will be on youtube videos. Unless you find a professional industrial designer has a channel on how to model organic shapes for injection molding, etc. You also want to search for mechanical engineering CAD methods.

The onshape tutorials cover the curves, the surfacing, the comb tools, etc. But they won't teach you why to put the curve here and not there, etc. That's probably contained in college classes for an Industrial Design degree.

Good luck:)

martin_kopplow · March 24

What you call 'complex modeling' is following the same rules as other modeling, only it is more complex. You need to set up a clean and robust history, think ahead a lot and keep track of what you did, in order to get resilient models that will accept later modifications without dissolving into digital debris.

Yes, experience helps a lot, but there are some pretty useful surface modeling courses in the learning center that can save you a lot of time.

jelte_steur814 · March 25

when you're looking for information on this subject. the proper search term is 'Surface Modeling'. Onshape has a number of courses, tutorials, tips and tricks, technical briefs etc on this topic. check out the learning center, that would be a good point to get started.
choosing and creating the contour curves right at the start is crucial.

javl0p_2 · March 25

Thanks for the suggestions.

Yes, I have been through all the Surface Modeling courses in OnShape I got a good understanding of concepts such curvature continuity and advanced surface features.

However, my question was more directed towards the methodology of such modeling. Something that is not dependent on the specific modeling software, but rather a transversal knowledge.

The thing is, even with the understanding of complex surface modeling, there are some products that I still would not be able to model.

STEG · March 25

You want to get better in Surface Modeling?
Only 1 path... Practice! Practice! Practice!

steve_shubin · March 26

In the Onshape app, open the PUBLIC section and do a search for the type of thing you would like to model. Then step through the Feature Tree to see how the part was made. I've learned a lot doing this.

Go look at Youtube videos regarding parts that you are interested in modeling. Even if the video shows something being modeled in a mechanical CAD program other than Onshape such as Solidworks, you still should be able to get some insight into how to go about modeling whatever it is that you are interested in.

Follow questions posted in this forum. You can learn a lot from those offering help.

MichaelPascoe · March 26

Post an example part here and I imagine you will have multiple different workflows from experienced users by the end of the day.

nick_papageorge073 · March 27

steve_shubin said:

In the Onshape app, open the PUBLIC section and do a search for the type of thing you would like to model. Then step through the Feature Tree to see how the part was made. I've learned a lot doing this.

Go look at Youtube videos regarding parts that you are interested in modeling. Even if the video shows something being modeled in a mechanical CAD program other than Onshape such as Solidworks, you still should be able to get some insight into how to go about modeling whatever it is that you are interested in.

Follow questions posted in this forum. You can learn a lot from those offering help.

I doubt much in the public space will be from professionals with a lot of surface design experience. I have not searched, but that's my hunch.

nick_papageorge073 · March 27

I have some experience with this. I worked for 15 years on mass produced children's products: infant carseats, strollers, highchairs, swings to rock them to sleep, etc. Everything was injection molded. Everything was to look fancy and organic.

It's not easy to model this way. It takes a whole different approach. For "block type engineering" you can model with simple sketches and extrudes. Then add rounds to smooth things out. When surface modeling, it's the opposite. You need to have the final shape very well thought out. The rounded portions are actually modeled and there are curves defining them. Rounded portions are not created with the "fillet" tool.

I was new to this in about 2004, and I had an Industrial Designer teach me how to model it, and teach me how to think through it. What helped me early on was making a clay model of the shape intended. Then tracing with a pencil to make a shallow groove on the model everywhere there needed to be a curve in the CAD system (I was using ProE, now called Creo, at the time). Then coming up with a game plan to make those curves in CAD, and then making the surfaces. Generally modeling like this is called boundary blends. Each boundary blend surface needs 4 curves to define its perimeter. (I forget if OS calls it something else, as I've not had to do this since switching to OS).

As I gained some experience, I was able to do the sketches on paper and skip the clay model. On those paper sketches I'd draw all the curves that defined the surfaces, listed the game plan, the order to make the curves in CAD, what planes I needed, etc.

These surfaces also have to be able to "reflect light" smoothly. When you look at a car, and move your eyes all across its panels, it's beautiful. The light reflects evenly in the sun. There are no "hot spots" of light. This is one of the goals of surface modeling. There are "comb" tools in all the CAD programs to see how they reflect light.

Disclaimer, this info is 15 years old. IDK if there are newer tools now to do it simpler. My last 5 years I was doing simpler "block style" modeling only.

Another disclaimer, I doubt this info will be on youtube videos. Unless you find a professional industrial designer has a channel on how to model organic shapes for injection molding, etc. You also want to search for mechanical engineering CAD methods.

The onshape tutorials cover the curves, the surfacing, the comb tools, etc. But they won't teach you why to put the curve here and not there, etc. That's probably contained in college classes for an Industrial Design degree.

Good luck:)

eric_pesty · March 27

Here's one example of a good video walk through of model. Definitely worth watching and hopefully YouTube will recommend some useful related ones...

https://youtu.be/IjcFotLmCx8?si=kkjeQGPPFNPWpTKt

javl0p_2 · March 27

nick_papageorge073 said:

I have some experience with this. I worked for 15 years on mass produced children's products: infant carseats, strollers, highchairs, swings to rock them to sleep, etc. Everything was injection molded. Everything was to look fancy and organic.

It's not easy to model this way. It takes a whole different approach. For "block type engineering" you can model with simple sketches and extrudes. Then add rounds to smooth things out. When surface modeling, it's the opposite. You need to have the final shape very well thought out. The rounded portions are actually modeled and there are curves defining them. Rounded portions are not created with the "fillet" tool.

I was new to this in about 2004, and I had an Industrial Designer teach me how to model it, and teach me how to think through it. What helped me early on was making a clay model of the shape intended. Then tracing with a pencil to make a shallow groove on the model everywhere there needed to be a curve in the CAD system (I was using ProE, now called Creo, at the time). Then coming up with a game plan to make those curves in CAD, and then making the surfaces. Generally modeling like this is called boundary blends. Each boundary blend surface needs 4 curves to define its perimeter. (I forget if OS calls it something else, as I've not had to do this since switching to OS).

As I gained some experience, I was able to do the sketches on paper and skip the clay model. On those paper sketches I'd draw all the curves that defined the surfaces, listed the game plan, the order to make the curves in CAD, what planes I needed, etc.

These surfaces also have to be able to "reflect light" smoothly. When you look at a car, and move your eyes all across its panels, it's beautiful. The light reflects evenly in the sun. There are no "hot spots" of light. This is one of the goals of surface modeling. There are "comb" tools in all the CAD programs to see how they reflect light.

Disclaimer, this info is 15 years old. IDK if there are newer tools now to do it simpler. My last 5 years I was doing simpler "block style" modeling only.

Another disclaimer, I doubt this info will be on youtube videos. Unless you find a professional industrial designer has a channel on how to model organic shapes for injection molding, etc. You also want to search for mechanical engineering CAD methods.

The onshape tutorials cover the curves, the surfacing, the comb tools, etc. But they won't teach you why to put the curve here and not there, etc. That's probably contained in college classes for an Industrial Design degree.

Good luck:)

Yes, this is my impression as well. There are plenty of videos of surface modelling through examples, but I have the feeling that they show you how they do it and not why.

Also, a lot of modelling that can be found on Youtube and similar is Freeform modeling based on subD, which I find interesting but its not my principal goal.

Thanks a lot for the answers!

javl0p_2 · March 27

eric_pesty said:

Here's one example of a good video walk through of model. Definitely worth watching and hopefully YouTube will recommend some useful related ones...
https://youtu.be/IjcFotLmCx8?si=kkjeQGPPFNPWpTKt

I will definately check it out! Thanks!

STEG · March 27

nick_papageorge073 said:

I have some experience with this. I worked for 15 years on mass produced children's products: infant carseats, strollers, highchairs, swings to rock them to sleep, etc. Everything was injection molded. Everything was to look fancy and organic.

It's not easy to model this way. It takes a whole different approach. For "block type engineering" you can model with simple sketches and extrudes. Then add rounds to smooth things out. When surface modeling, it's the opposite. You need to have the final shape very well thought out. The rounded portions are actually modeled and there are curves defining them. Rounded portions are not created with the "fillet" tool.

I was new to this in about 2004, and I had an Industrial Designer teach me how to model it, and teach me how to think through it. What helped me early on was making a clay model of the shape intended. Then tracing with a pencil to make a shallow groove on the model everywhere there needed to be a curve in the CAD system (I was using ProE, now called Creo, at the time). Then coming up with a game plan to make those curves in CAD, and then making the surfaces. Generally modeling like this is called boundary blends. Each boundary blend surface needs 4 curves to define its perimeter. (I forget if OS calls it something else, as I've not had to do this since switching to OS).

As I gained some experience, I was able to do the sketches on paper and skip the clay model. On those paper sketches I'd draw all the curves that defined the surfaces, listed the game plan, the order to make the curves in CAD, what planes I needed, etc.

These surfaces also have to be able to "reflect light" smoothly. When you look at a car, and move your eyes all across its panels, it's beautiful. The light reflects evenly in the sun. There are no "hot spots" of light. This is one of the goals of surface modeling. There are "comb" tools in all the CAD programs to see how they reflect light.

Disclaimer, this info is 15 years old. IDK if there are newer tools now to do it simpler. My last 5 years I was doing simpler "block style" modeling only.

Another disclaimer, I doubt this info will be on youtube videos. Unless you find a professional industrial designer has a channel on how to model organic shapes for injection molding, etc. You also want to search for mechanical engineering CAD methods.

The onshape tutorials cover the curves, the surfacing, the comb tools, etc. But they won't teach you why to put the curve here and not there, etc. That's probably contained in college classes for an Industrial Design degree.

Good luck:)

You can ahve a look at Greg Brown's YouTube channel here:
(32) Greg Brown - Onshape - YouTube

Is there a theory for complex modelling?

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