From Roll20 Wiki
Using The Align To Grid Tool
Sometimes you might want to use a pre-made battlemap that already comes with its own gridded surface. If you're having difficulty getting your image's grid to match Roll20's, we have an alignment tool that will make this task easier.
- Zoom in to 150%
- Make sure you're on the Map & Background layer
- Right Click on your map image and choose Advanced -> Align to Grid
- Click and drag to trace a 3x3 (three across & three down) square box aligned with the grid on your map (we're ignoring the Roll20 grid for right now). You don't need to be pixel perfect here, but the more accurate the trace, the less fine-tuning you'll need to do later on.
- When you let go of the mouse, a new window will appear. If you're satisfied with your tracing, click on the "Align to Grid" button to confirm.
- The Grid Alignment Tool should resize your map to match fairly closely to Roll20's grid. Use the horizontal and vertical scaling transformers on your image to fine-tune the grid alignment.
Further tips on aligning
If you have problems aligning to grid, this is a breakdown from Gauss.
First let's go over the steps to align a square grid map.
This assumes you have already placed the map on the map layer and that you are on the map layer.
1) Start by setting your zoom to 150%
2) Next, right click on your map and select Advanced -> Align to Grid
3) Trace a 3x3 section of your map's grid and release and click the align grid button
Now for the fine tuning:
4) Hold down the alt key and with the mouse move the map so that the grid is aligned. Doing this in the center of the map will produce the best results.
5) You can use the scaling transformers (light blue boxes at the edge of your map) to resize the map to better fit.
- 5a) For a more precise fit right click on the map and select Advanced -> Set Dimensions. For the vertical map lines if the line is to the left of the Roll20 grid lines then increase the width in Set Dimensions. If the line is to the right then decrease the width in Set Dimensions. For the horizontal map lines if the line is above the Roll20 grid then increase the height. It the line is below the Roll20 grid then decrease the height.
6) Repeat steps 4 and 5 until the grid matches throughout your entire map.
I have a hex (H) map. How do I align that?
1) Drop the map onto the map layer.
2) Use the scalers (little boxes on the edge of the image) to get the hex map near the same size as the hex grid.
3) Find the middle of the map by doing the following: Height: count the number of vertical hexes. The middle of the map should be the halfway point. Example: If your map is 60 hexes tall the halfway point is the line between hex 30 and 31. Width: count the horizontal hexes. The middle of the map should be the halfway point. Example: if your map is 80 hexes wide the halfway point is the line between hex 40 and 41. The two mid points should create an intersection which is the middle of the map. This is where you will make adjustments from.
4) Align the intersection at the middle of the map. You can do this by holding Alt and aligning the map intersection to the grid intersection.
5) We will align the horizontal map lines first. Right click on the map, select Advanced -> Set Dimensions. If the lines (above the starting line) are above the Roll20 grid then decrease the height. If the lines are below the Roll20 grid then increase the height.
- 5a) You may need to repeat step 4 if the alignment point gets offset (this probably means the alignment point is not the center of the map). Keep repeating this until the horizontal map lines are perfect.
6) We will align the vertical map lines next. Right click on the map, select Advanced -> Set Dimensions.
If the lines (to the right of the starting line) are to the right of the Roll20 grid, then decrease the width. If the lines are to the left then increase the width.
- 6a) You may need to repeat step 4 if the alignment point gets offset (this probably means the alignment point is not the center of the map).
7) Keep repeating this until the vertical map lines are perfect.
For Hex (V) just reverse all of the above instructions that involve width and height or horizontal and vertical.
Further accuracy on aligning grid
Here are some other tips and tricks:
How to get a more accurate Align to Grid as a first step:
- Increase the Page Size to a very large number (such as 200 by 200). You can do this in the Page Toolbar and adjust the settings for the map you are working on.
- Set zoom to 50% and then expand the map size to fit the Page Size.
- Set zoom to 150% and use the Align to Grid tool.
- Reduce the zoom to 50% and move your map to the top left corner of the page.
- Decrease the page size to match your map size.
- Return the zoom level to 100% and follow the fine tuning tips above.
Ripped map from PDF
I ripped my map out of a PDF and the grid is is too small even when set to 150%!
Thankfully this has a simple solution:
- Follow the above steps to align the map to the grid.
- Use the Set Dimensions tool to increase the size of the map. Make sure you use a multiple of 2. Example: If your current dimensions are 3640 by 5040 then double the dimensions to 7280 by 10080.
- Increase the Page Size (in the Page Toolbar) to fit the new size of your map.
- You may need to double the Grid size and halve the Scale size. You can find both fields in your Page Settings in the Page Toolbar.
- Make any final adjustments such as using Alt and move the map reposition it if necessary.
There are other methods to solve this problem but most of those are more complicated. If you find that using a grid size other than 1 creates a problem fire off a message to me and I can walk you through how to fix this while keeping the grid size at 1.
I know the pixel dimensions, how to adapt to the 70x70 pixels of Roll20?
I have a map grid that I know is 64x64pixels. I want to set the Roll20 grid to 64x64pixels. How do I do this?
- Use the Set Dimensions tool to set the dimensions of your map to a multiple of the grid. Example: if your grid is 50 squares by 32 squares and uses 64pixels by 64pixels then set the dimensions to 3200 by 2048. This presumes that there are no partial grid borders. If there are you will need to use the Align to Grid tool.
- In a calculator divide the grid size by 70. This will produce a decimal value. Example: 64/70 will result in 0.91428571...
- Set your Grid Unit Size to the decimal value you calculated. This can be found in the Page Settings for your map in the Page Toolbar.
- Now we need to fix the Scale. Divide the scale you wish (such as 5feet) by the decimal value you calculated in step 1 and put that number in the scale. Example: 5/0.91428571... will result in 5.46875. Click OK.
- Now hold down Alt and move the map to align the grids if necessary. They should line up perfectly.