All About Part Workbench- Intermediate Level

This article will take you through the intermediate level of working with Part Workbench. Before you dive into the topic, let’s get an overview of Part Workbench.

What is Part Design Workbench in CATIA?

The core for FreeCAD's solid modelling capabilities is the OpenCASCADE Technology (OCCT) kernel, a professional-grade CAD system with powerful 3D geometry creation and manipulation. The Workbench Part.svg layer of Part Workbench is placed on top of the OCCT libraries. The OCCT geometric primitives and functions are accessible to the user. Practically all 2D and 3D drawing features in every workbench are built on these functions provided by the Part Workbench (Workbench Draft.svg Draft, Workbench Sketcher.svg Sketcher, Workbench PartDesign.svg PartDesign, etc.). The Part Design Workbench in CATIA is therefore regarded as the most crucial component of FreeCAD's modelling capabilities.

What Happens At The Intermediate-Level Of The Part Design Workbench?

 

• AVOID UNNECESSARY USE OF PLANES

The main idea behind this topic is the same as what we have discussed previously in sketcher workbench, i.e use of unwanted construction elements that help you in building your sketch but make the sketch crowded. The same concepts are applied, but here we avoid the plane system's overuse. This topic can be explained in two different situations. 

a. When the object is away from the origin,

Let's take the following example.

Each plane is offset from the origin to create its respective pad/pocket. But this way of plane creation is not required to get the final result. Only the origin planes i.e xy,yz and zx are required to create this final result.

Let's start with the 2nd pad that was created using the 2nd plane.

Above are some major outside dimensions that are required to create the pad.

First, I will start my work with the help of yz plane; I will create the same sketch that I created before inside the offset plane.

Now let's extrude the sketch using the pad option. Previously we offseted a 50mm plane to create a 20mm thick object. By considering this, I will pad my sketch about 50mm+20mm.

Now comes the important part of this topic. We know that this is not the result we want. In Order to get that we need to first click on the bottom right more option and in the second limit give a -50mm value. By doing this our 2nd limit pad will move in the negative direction and we will get our required result.

So without the help of an additional plane, we were able to get our required result.

Now let’s create the slot with the same method.

Now create the same sketch over the yz plane and create the slot with the help of the pocket option.

Same way, you can create all the remaining pad/pocket without the use of additional planes.

b. While mirroring an object

Method 1

In this situation, if we want to mirror the left-side object towards the right side, we need to offset a plane in the exact middle.

For that select the object that we want to mirror from the tree. Here it is pad 2(don't click on the complete body, just select the object that needs to be mirrored from the tree). Use the mirror option to mirror the pad 2.

Working on this method, i.e by adding an extra plane for mirroring, is completely fine. But this type of model can be mirrored without the use of additional planes. 

Method 2

For that, let's recreate the body again.

The first sketch is moved in such a way that it is now symmetrical with the origin.

Now I can just pad the sketch with the same method that we learned before.

Now for the opposite side body, I use the mirror option to mirror it over to the other side. Here I just use my origin yz plane instead of offsetting a plane in the middle

Method 3

For both case 1 and case 2, we could also use the same negative pad method to bring it over to the other side. Here we will use the same sketch for padding in both directions.

Method 1 - New Method

Method 2 - New Method

All of the above topics, do not explain why you can't use additional planes for these models. Just showing you that, without the use of additional planes, we are able to create these models. Also, additional planes, in turn, make your tree look bigger. Try to avoid them if not necessary.

2. USE OF MEASURE BETWEEN/MEASURE ITEM OPTION WHILE DOING PAD/POCKET

We already know the use of the measure between and measure item option. They help identify an object's dimension(length, diameter, area, thickness etc.). These same measure options can be used while doing a pad/pocket in between the unknown measurements. 

Let's take the below example.

Here, I need to create that pink block from the edge of the pocket towards my origin with a 20mm depth. Since we are taking the sketch from the origin and then creating the pad from the edge of the pocket, we need to use the option from the pad command that we learned in the previous session. 

But problems arise when we are not aware of the starting distance. Here we know that the slot length is 70mm from the other side. Suppose we need to find out the total length and slot length after creating the slot. We need to measure as we did in the above image, and then we need to create the block with 20mm depth. Instead of doing that, there is an additional easy method to measure the distance in between while we are doing an operation. 

Let's take the following situation.

Now let's assume that we don't have any dimensions that help us in creating the pink block.

I will start with my pad operation. I will open my pad definition dialogue box and on the first limit, I will right-click on my length block and select measure between options.

Now the ‘measure between’ dialogue box will appear and we want to select the total length of extension from the origin plane to the starting end of the pocket.

Also, uncheck the keep measure option and click ok for measure between an information dialogue box that appears afterwards.

(Note:- if you want the measurement to be displayed, then you can check the keep measure option, otherwise not required)

Now we have our first limit set. Now I need to click on more options and set the second limit. We know that the total length is 120mm, so 120 - 20mm thickness of the body will get the total length as 100mm. So I need to give a negative value (-100mm) to the second limit.

Hence we were able to figure out the unknown distance with the help of measures between options.

3. USE OF REMOVE FACE OPTION

There are situations where we want to remove some operations that we have performed before but we don't want them to get removed permanently because after some time we need it back in its original position on our model. These situations may occur especially at the time of remastering when we want to remove some operation temporarily from the non-parametric body so that it will be easy for us to create the new remastered model.

You may wonder if the same can be achieved using the deactivate option. But there are a few limitations for this option and also for a non-parametric body we don't have the deactivate option to perform.

Let's take the following example where I have performed a pad and fillet.

Here the body is parametric. How can we say this because all the operations and sketches are highlighted in the tree.

(Parametric bodies are those models in which we are able to do modifications if required. This modification/editing is not possible in non-parametric bodies.)

Suppose, I want to remove one of the fillet edges temporarily. Let's try to achieve this condition by trying both remove face and deactivate options.

Deactivate Option

Let's start first with the deactivate option and see if we are able to achieve the required result i.e. only one fillet getting removed.

When we tried to deactivate one of the fillets, the entire fillets were getting deleted. This is because instead of deleting that particular face, the entire operation is getting deactivated. If you check the tree you will get a clear picture. 

Let's activate the fillet back by following the same step.

Remove Face

Now let's try the same using the remove face option. You can find the option from the dress-up feature.

Let's select the same fillet(face) that we tried before.

We will be getting the required result with extra remove-face operation inside the tree.

If you want to bring back the fillet that got removed, just delete the removed face from the tree.

Let's check the same for non-parametric solids.

For that, right-click on the part body and select copy.

Now click on file-> New-> Part. New part workbench window is opened. Right-click on the main tree and select paste special and select As Result.

Now we have a non-parametric body.

If you check the tree, now instead of pad and fillet, there is only one solid body with an isolation symbol. So, now we have the nonparametric body that doesn't have either dimension or operation details on it. 

These are the important steps in the intermediate level of Part Design Workbench in CATIA.