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 the align to grid tool to help make that easier.
Using The Align To Grid Tool
- 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.
What follows is a video breakdown on how to use the tool:
Further tips on aligning
If you have problems aligning to grid, this is a breakdown from Gauss.
Follow these steps to align a square map. These steps assume you have already placed the map on the map layer, and that you are on the map layer.
- Start by setting your zoom to 150%.
- Next, right click on your map and select Advanced -> Align to Grid.
- Trace a 3x3 section of your map's grid and release and click the align grid button
To fine tune the map:
- Hold down the Alt key. With your mouse, move the map so that the grid is aligned as closely as possible. Doing this in the center of the map will produce the best results.
- Use the scaling transformers (light blue boxes at the edge of your map) to resize the map to better fit.
- For a more precise fit, right click on the map and select Advanced -> Set Dimensions.
- If the vertical map lines are to the left of the Roll20 grid lines then increase the width.
- If the vertical map lines are to the right of the Roll20 grid lines, then decrease the width.
- If the horizontal map lines are above the Roll20 grid lines, then increase the height.
- If the horizontal map lines are below the Roll20 grid lines, then decrease the height.
- Repeat the above step until the grid matches throughout your entire map.
Follow these steps to align a hex map. Note: Be sure to choose the right grid style on the Page_Settings.
- Drop the map onto the map layer.
- Use the scalers (little boxes on the edge of the image) to get the hex map near the same size as the hex grid.
- 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. For 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. For 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.
- 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.
- 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. #*Repeat the above step if the alignment point gets offset. This can happen if the alignment point is not the center of the map. Keep repeating this until the horizontal map lines are perfect.
- 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.
- Repeat the above step if the alignment point gets offset. This can happen if the alignment point is not the center of the map. Keep repeating this until the vertical map lines are perfect.
For Hex (V), 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.
Another method for aligning maps with baked-in grids
- Right click on image and set the dimensions to 700x700px (10 cells each way).
- Right click on image and set "is drawing". You can skip this if you are absolutely certain the map edges are exactly on a grid line (there are a lot of maps, especially older ones, that aren't).
Those 2 steps give plenty of area to be able to grab the image and to be able to see some of the details (especially the on map grid) well.
- Inset the image so that the upper left corner is in one row and column from the top and left edges of the map.
- Set the Roll20 grid to something that can very easily be seen against that particular map.
- Drag the bottom of the map downward until the map grid lines along the left edge line up with the Roll20 grid. Enlarge the Roll20 map page as needed to get enough room.
- Drag the right edge out until the map grid lines along the top edge line up with the Roll20 grid. Enlarge the Roll20 map page as needed to get enough room.
- Some old maps didn't have a grid line at the edge of the map, and instead ended about halfway into another row/column of cells. This is why you set the image to "is drawing", so that you can align your upper left corner without snapping to grid. Adjust as needed to get any overhang into the border row/column.
- Once you have the map all stretched out to where things line up with the grid, decide if you are content with the display resolution of the map. If it is blurry, then use the "set dimensions" to set the image size to half. Then set the grid size to .5, adjust the upper left hand corner alignment if needed, and reduce the size of your map page to match the current image size plus any border cells you want to maintain.
- Turn the Roll20 grid fully transparent, so that you are only seeing the map grid.
Once that is done, the optional (though recommended) step number 10 is to use your pro subscription perk of the transmogrifier to save this map to a map library game so you never have to go through that setup again for that map should you desire to use it again in the future.
The preceding workflow comes from one of our Pro members, Kraynic, with many thanks from us here on the team!