|Step 2: Features for Stretching >>
In this article:
- Adding a stretch measure
- Additional information
- Next step
We will need to add some additional parameters to our models before they are capable of being stretched. We will be using the Model Lab component tab for this process.
Catalogue stretch will only work with cmsym models. Any existing cm3D models will need to be converted into cmsym models before they can be used. To do so, you can use the Batch Converter, or simply open your file in Model Lab and save it in cmsym format.
Start off by launching Model Lab, and then save your cmsym model files in it. What we will need to do here is to add stretch measures to our models. We will only be dealing with the contents of the Stretch section during this process.
Adding a stretch measure
Inserting & naming stretch measures
First, click on Add ("+"). You will notice that grids have appeared around your model. You are now able to place a stretch line on that grid. Stretch lines are made up of a start stretch point (denoted by a green sphere) and an end stretch point (denoted by a red sphere).
The positions of these points are important as they represent where your stretch connectors will ultimately appear. It is vital that these points are placed at the correct positions on the grid, as any small difference can result in the stretch behaving unexpectedly.
The order of placement also matters, as you will first place the start point, followed by the end point. In Model Lab, this also affects the direction of the stretch line, which is the direction that the model is stretched in. This distinction between the start and end points will be highlighted later when we look at setting up the product in Catalogue Creator.
When inserting stretch points, pressing the Up and Down arrow keys will change the grid resolution. Grid resolution determines the number of grid lines that further sub-divides the grid.
Changing grid resolution
Once both stretch points are placed, your model will then be covered by different colored sections. You are now able to insert cutoffs to create sections, and you can insert as many cutoffs as you want. Sections help define which parts of your model are stretched. Once you have inserted at least one cutoff, end the animation (by pressing the Esc key or moving your mouse over the tools on the left) and the stretch measure will be inserted.
Stretch measures added
In the image above, we can see that the purple and yellow sections both have a 50% value, while the blue section has a 0% value. When a model is stretched, we are changing the length of the model in the direction of the stretch line. These percentages describe how much of this length change is applied to each section of the model. The sum of these percentages must add up to a 100%, or it may result in some unexpected behavior.
Stretching a model with highlighted sections
In the video above, we can see that only the purple and yellow sections are changing in length, while the blue section does not change at all. As mentioned previously, 50% of the length change is applied to both the purple and yellow sections accordingly, with the blue section receiving no change. You can try tweaking these percentages to see what different results you can obtain.
Let's talk about the Move and Scale checkboxes. These properties determine how a section is stretched. A section can only be move stretched or scale stretched.
- Move - adds/removes length to a plane in your section. To be specific, it adds/removes length at the start cutoff of the section (except the first section, which only has the end cutoff).
Scale - tries to scale the entire section to fit the new total length of that section, essentially stretching every part of that section in the direction of that stretch line.
Move stretched sections
Scale stretched sections
When inserting sections, pressing the Up and Down arrow keys will change the number of help points.
Changing number of help points
Measure IDs are important as the stretch measures will be exposed in Catalogue Creator as parameters of the model, and will be identified by their IDs. Enforcing proper naming is recommended to avoid any future pains with finding the correct stretch measures to use.
You can change a stretch measure's ID by selecting it and then clicking the Set ID button. A dialog will pop up where you can type in the new ID and press Enter to complete the process. Refer to the Inserting & naming stretch measures video to see this in action.
In all the examples above, we have started inserting stretch measures without any layer selected, and a grid would appear around the entire model. However if we have any layers selected, the grid will appear around their combined bound instead.
Different grids based on selection
Incorrect placement of measures
Try to avoid having a measure that lines up with a section cutoff of another measure. These cases can result in unpredictable stretch behavior, as we can't be sure where our measures will end up after stretching.
The Depth measure is on top of a section cutoff for the Width measure
In the case above, we expect the Depth measure to always be in the middle of the table. However after stretching the Width measure, we ended up with this.
The Depth measure is in the wrong position
The Depth measure did not move at all as the Width measure was stretched, as it seems that the Depth measure was within the first section of the Width measure. In this case, we do not want this result because when we use this model for our catalogue product in CET, our connectors will end up out of place.
Grid resolution controls the number of grid lines that appear when inserting a new stretch measure.
Help points controls the number of help points (tiny green spheres) that appear on the stretch line being inserted while inserting sections. They act as additional points that can be snapped to for ease of use.
Show sections displays all the sections of the currently selected stretch measure when checked.
Resolve to 100% distributes/removes the remaining/excess percentages among the sections that are being used for stretch (sections that are not 0%).
Swap points swaps the start and end stretch points of the currently selected stretch measure, thereby reversing the sections and direction of the stretch line.
Now that our stretch measures are added and named appropriately, our model is ready for use. Verify that the stretch measures are working correctly by test stretching the model for each stretch measure.
If everything looks right, then this step is complete, and we can now move on to configuring our catalogue. We will begin by looking at setting up the domain that will be used for our measures. Continue reading on the next page, Step 2: Features for Stretching.