Sculpted cakes can be challenging! My best advice is to plan ahead but to also be flexible.
Thinking in 3D is difficult for me. To help, I try to think in layers and use cut outs.
When I planned for this cake, I thought about the shape of the bottom layer of cake.
I sketched out the shape and cut it from a piece of cake board.
The client and I discussed the guest count but also the size of the cake. We decided on about 60 servings. I sketched out the base of the bulldozer and sized it to be about 7 1/2 x 10. I baked a 1/2 sheet (11 x 15) and a 8" square. I used an Agbay to torte the 2" cakes to 2-1" layers. I flipped over the cake board and cut the first layer of cake to be the bottom of the bulldozer.
The wheels of the bulldozer curve inward and the front of the bulldozer changes shape so I change the template a bit and cut the next layers. Notice at first I am just stacking to see that I am getting the shape. This makes it easy for me to remove a layer and adjust.
Once I have the general shape, I fill and carve a few more of the details.
Just like any cake, I stop along the way to add structure where needed. For me, that is usually every 4 or 5 layers. I've added a little piece here to support where the back edge comes farther out than the bottom layers.
Once I have that bottom half completed, I crumb coated. I wanted to get a clear idea of the shape. I then used my template to cut the top cab.
At this point, I realized the shape of the wheels was a bit too high and not quite right. Remember I said be ready to adapt! I carve the wheels a bit more to shape and finish the crumb coat.
I like to chill the cake between crumb coating and final frosting.
Now that I have the shape of the bulldozer, I need to make the front piece. I usually make a template for these but I like to wait until the cake is sculpted in case I need to make any adjustments.
First, I hold the template up to the cake to make sure it is the right shape and size. I roll out the gumpaste and use the template to cut. For the shape of this one, I used 2 - 5" foam dummies. I held them in place with a 6" dummy until they dried enough that they didn't move. I let these sit overnight.
In a post about covering a cake in fondant,I used this very same cake to show how to measure how much fondant you need to cover a cake.
Measure long ways and short ways across the cake. I like to use a measuring tape so that I can fold it along edges.
Roll the fondant, cover the cake, and trim. Yes, I know I worded that as though it was very easy ;). It's ok if this takes a few tries. Start at the top and work your way down fanning out the fondant so it doesn't wrinkle. This video may help.
Now we get to decorate!
I cut templates for the windows and front plate. Outline these with a vein tool. This will help center them in place. Cut the pieces from black fondant. Flip over the side window for the alternating side. Be sure to smooth any rough edges.
Measure the wheel spaces as well and cut this piece of fondant. Fold the fondant over the wheels and use an X-acto knife to trim.
Use a food grade paintbrush to paint diagonal streaks of silver luster dust on the windows. I like to leave some darker than others because it adds to the illusion of glass.
I honestly do not remember exactly what circles and shapes and petal cutters I used to make the clockwork like parts to the wheels. Have fun and be creative!
I do recommend placing those first so you don't bump anything while doing the next part. Using the same measurement as before, cut a strip of black fondant. Place it along the top edge then tuck under the bottom.
You may recognize this Wilton mold . I used it to make the tire treads and a extruder to outline the windows and front.
I covered a wooden skewer with black fondant then added the little curved spout at the top. To make the little lights, I rolled a ball of fondant and cut it evenly into 2 pieces then shaped them with my hand. I placed them and added tiny white squares using this set of fondant cutters.
If you don't have a black cake board, cover one with black contact paper like this one. Be sure to use Contact brand because it is waterproof and non toxic. I used my chocolate buttercream to mimic mud. Measure the cake to pick placement. I held it above and positioned it a few ways before deciding the right spot. I then gently placed the other pieces to ensure they would fit.
Cover 2 thicker bamboo skewers or wooden towels with sharp points in yellow fondant. pierce them into the board and add the end caps.
So that the shovel piece perfectly matches, I cover it with fondant. It's my experience that gumpaste dries a different color and is almost impossible to match. I first cover the back side then the front and rub the lines to smooth. I used the veining tool to make the line at the bottom. I used a tiny little piece to add door handles.
Woohooties! This little bulldozer is ready for the party.